Rohde & Schwarz CMU200

[ZL1CVD]

Just upgraded an 8924C for a CMU-200. It has a fault - internal RF loop path 1 test fails. Does anyone have any ideas where I should start? Also does anyone happen to have service manual with circuits - the one i have is missing all module exploded diagrams and circuits. Next step for me it to install a SSD. Cheers.

[Nuno_pt]

Not very easy to find that detail manuals in the R&S stuff.

Try run RF Self Test < http://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_news_from_rs/167/167_CMU200selftest.pdf >

I'm also looking to buy one of this because of the Spectrum Analyzer and Tracking Generator till 2.7GHz, and also for the Audio Part, so I can measure the RX sensitivity of the radios with Power at 10dB Sinad.

 

[ZL1CVD]

I have been playing with it for a few hours now. I ran most of those tests and all reported fine except the RF loop back.

There is no tracking generator that I can find. Also no RF demodulation which is a big shame. So for general ham radio use, you have spectrum analyzer, RF generator & audio generator/analyzer.

Spectrum analyzer is very nice and allot faster than the older HP's I'm used to (8924 & E8285). But these older HPs still offer allot that this doesn't. Well, that I haven't found yet....

[Nuno_pt]

The RF Generator or Signal Generator from what I see can be use to be feed in the unit, to measure one filter, and don't know if it will track?
But for some prices of this units, an SA, Signal Generator, and Audio generator and analyzer, it's ok.

Some findings, from what the CMU have:

" The CMU200 is great bench-top unit. The RF gen covers 100kHz - 2.7GHz (0.1Hz steps, -130dBm to -27dBm up to 2.2GHz, -130dBm to -33dBm between 2.2Ghz and 2.7GHz), the power meter covers the same range in wideband mode and 10Mhz to 2.7GHz in selective mode, and measures depending on the input and type of signal from -80dBm to +53dBm (calibrated, not unleveled). The SA goes from 10Mhz to 2.7GHz, the span from zero to full (which many vector SAs in such testers can't do), RBW is from 10hz to 1MHz in 1/2/3/5 steps. My unit is the newer model with USB instead of PS2 ports for a keyboard and has the optional 2nd RF generator (same range as the first one) and the optional audio generator/analyzer (20Hz to 20KHz) which is nice. It's fast and has a clear and intuitive UI.  "

[ZL1CVD]

Yes it has all that but I can't see how to make the gen track. And yes, have to agree, for the price I paid, I did get a good deal.

From what I have read, some are saying the CMU200 PSU are starting to fail also.

The CMU screens have RF shielded glass in front of the TFT - mine has deteriorated badly - a green oxidization from edge working its way in. Replacement from R&S will be mega $$. I've just pulled it out and will get the local glass shop to cut a bit the same size. I'm not worried about emissions and this environment isn't going to create anything that will effect the measurements I make with it. 

For all its greatness, I can still pick up and E8285A or 8924 for around same price and they do allot more - but allot slower and will need almost all electro caps in PSU & display changed. The CMU could easily do the same as the hardware is more than capable. I wonder if its possible to hack its software to add features....

[Nuno_pt]

From what I can see the RF Generator (Signal Generator) is not an tracking generator is because the CMU is a VSA and not one sweep spectrum analyzer, you can make the RF Generator produce an -10dB to one frequency across the DUT and watch the result on the SA.

But will not sweep across the spectrum, like the DSA-815.

But I agree for the price that some run, get one SA, Signal generator, audio generator, THD, etc, it's a great deal.
For watching filters, see tolerances in the radios with the RF generator, and audio generator with 1kHz.

I'm looking for one too, then one Communications system tester, like IFR or Motorola.

[Wuerstchenhund]

There is no tracking generator that I can find. Also no RF demodulation which is a big shame. So for general ham radio use, you have spectrum analyzer, RF generator & audio generator/analyzer.

It doesn't have a tracking generator, simply because it's a communications test set designed for digital communication standards like GSM, W-CDMA, Bluetooth or GPS. What it has are one or two (depending on the options) RF generator(s), a Spectrum Analyzer (sweeping VSA), an RF Analyzer, a power meter (wideband and narrow band), and a 20 tone audio generator/analyzer, all in one box.

You can replicate the tracking generator if you connect the CMU200 to a PC and command the RF generator via software to "sweep" through a  frequency band while the SA is set to max hold. The dwell time for the generator needs to be larger than the sweep time, so it will be slow. But it works.

Much easier and quicker however is just using a wideband noise source, which you can even build yourself.

Spectrum analyzer is very nice and allot faster than the older HP's I'm used to (8924 & E8285). But these older HPs still offer allot that this doesn't. Well, that I haven't found yet....

8924 and E8285 are older test sets that, while supporting early digital standards, were pretty much designed for the analog communication systems back then as well as cable and antenna testing, and because of that they offer more analog functionality than modern comms test sets like the CMU200. However, they also come with all the typical disadvantages that many other cell phone test sets come with, like split frequency bands with gaps or forced coupling of RBW and span for the SA part, which actually makes it more like simple "spectrum monitors", not full scale SAs.

In comparison, the CMU200 offers a full scale SA with single frequency band without "holes", and the SA lets you set span and RBW independently as it should be, and optionally even shows you the I/Q components of a signal.

If TG-like functionality is important then have a look at the AGilent E7495A/B, which is a portable unit with a VSA (2.5/2.7GHz), an RF generator, an AWG and a wideband noise source so it can act as a Network Analyzer, as well as a GPS Reference.

[ZL1CVD]

Thanks for the comments Wuerstchenhund, very helpful. 

The more I play with the CMU200 the more I can see its going to be a great addition to my bench. I now have a SSD on order along with replacement RF front end & B11 OCXO. Wide band noise source is now on the to-do list. Then to look into connecting & controlling it with the PC.

The R&S CRTU-RU also looks like something to save up for..

[Wuerstchenhund]

The more I play with the CMU200 the more I can see its going to be a great addition to my bench. I now have a SSD on order along with replacement RF front end & B11 OCXO. Wide band noise source is now on the to-do list. Then to look into connecting & controlling it with the PC.

I think R&S has some Windows programs for the CMU200 (FreeRes?), but I've never used them. Maybe they

The R&S CRTU-RU also looks like something to save up for..

Not really, because it's pretty much just a CMU200 with an additional Windows 2000 partition for automated cell phone testing but without the audio generator/analyzer. So unless you plan to do cell phone production testing it doesn't really offer anything above the CMU200.

[Nuno_pt]

Wuerstchenhund, can´t the RF Generator be feed into the CMU across the DUT on one given frequency and watch on the SA.

Like the DUT is an BPF for 144MHz, and you feed the RF Generator across the DUT and watch on the SA.

Can you post some images of yours.

[ZL1CVD]

I'd like to also get CRTU-RU as it is running Pentium III 933MHz vs Celeron 650MHz, has front panel USB slots and more RF options fitted as standard. Having windows installed, it should also have drivers for the hardware and hopefully DLLs I may be able to use with something like Delphi.
Does anyone know if the CRTU-RU has a touch screen?

[tmbinc]

The CRTU-RU does not have a touch screen, and the Windows driver unfortunately do not expose necessary functionality for SA (RX sweep, for example).

[Wuerstchenhund]

Wuerstchenhund, can´t the RF Generator be feed into the CMU across the DUT on one given frequency and watch on the SA.

Like the DUT is an BPF for 144MHz, and you feed the RF Generator across the DUT and watch on the SA.

Sure you can do that, no problem. But usually a single frequency isn't helpful, so you'd probably want to 'sweep' through a certain frequency band. On the CMU200/CRTU-RU, you'd have to do this either manually (i.e. scroll through the frequency band slowly with the rotary knowb) or better, do that with an external PC which calls up a list of frequencies.

Can you post some images of yours.

What kind of pictures? I don't have mine any longer as  the 2.7Ghz bandwidth wasn't enough for my needs but I might still have some photos of the device and screenshots.

I'd like to also get CRTU-RU as it is running Pentium III 933MHz vs Celeron 650MHz, has front panel USB slots and more RF options fitted as standard. Having windows installed, it should also have drivers for the hardware and hopefully DLLs I may be able to use with something like Delphi.

The CRTU-RU doesn't have more options as standard as the CMU200. Both share the same instrument platform, the differences are that the CRTU lacks the audio generator/analyzer and instead of the speaker comes with a passive RF splitter/combiner.

The Windows software is made for automated testing, i.e. scripted test procedures. For that it uses Microsoft Visual C/C++ as an editor. The capabilities of the Windows drivers are simple, i.e. it lets you select an input/output and put the instrument in a certain state, but as far as I know you can't access the low level functionality of the various subsystems (RF generators, RF receiver, audio analyzer, power meter) so writing your own 'spectrum analyzer' application isn't possible.

Also, although the platform itself is identical to the CMU200, CMU200 modules normally don't work in the CRTU and vice versa.

Does anyone know if the CRTU-RU has a touch screen?

No touch. As I said, it's pretty much the same hardware as in the CMU200.

If you want a faster 'PC' (called 'FMR' in R&S speak) then I'd rather look for a newer CMU200 than a CRTU, as the CMU is more versatile.

[msraya]

Hello all!!

I have one unit that comes to me the next friday with B11(simple ocxo),  B41(audio analyzer) and B95(second RF generator)...  I am looking for KingSpec ssd pata cheap chinese units in aliexpress right now..

I printed the user manual and the service manual and I'm studying it right now... I come from RIGOL DSA-815 and Stabilock 4032...  I'm interested in program it using VISA library in Python, in order to measure several classic parameters in LNA, mixers, etc.. 

Did you write a review for the instrument, Wuerstchenhund??

Very nice instruments, indeed..
Manuel

[ZL1CVD]

I'm looking for a CMU200 user manual that covers the standard analog features - sig gen, power meter, spec an, audio an, etc. What I have here is service data and manuals specific to various GSM & CDMA options - which this one has. Want to get more of a handle on basic stuff like navigation, changing units of measure, Etc. Can anyone share a link?

BTW my screen had badly oxidized screening around edges. Replaced with standard 3mm glass cut to 185x141mm square. Its not screened but doubt this will effect home workshop use. Looks 100% better.

Also have a 32GB KingSpec SSD on order - huge overkill on size I know but will give me room for DOS, Windows & Linux partitions. 

Cheers, Chris - ZL1CVD

[_Wim_]

The manual you need is 1100.4903.12-04, but I cannot find a direct link online and it to big (16Mb) to attach here. If you sent me a pm with your email address, I will sent it to you.

[_Wim_]

Has anybody found some reference about the max DC input voltage the CMU200 can handle. The only thing I have found about this is this thread: (https://www.eevblog.com/forum/testgear/crtu-ru-input-coupling/), but so far I have not been able to confirm this is correct and applicable to the CMU200 also.

[msraya]

Hello everyone!

I get the equipment and I test it.. Hopefully the unit is working well except for some uncalibrated power measures.
The RF generator and RF spectrum analyzer is nice, the DANL is not bad and outperforms my RIGOL by a little..

The main problem with the unit is that it cannot make Audio analysis and RF analysis at the same time.. so I cannot adjust FM equipment with the RF generator and SINAD meter, nor I can use an external demodulator over the IF output and at the same time do deviation measures with the Audio analyzer.. 

I think I will need the AMPS extensions K29    and that must be purchased separately.. so only RF generator, selective Power meter, frequency counter, Spectrum analyzer, Audio Generator and SINAD meter for me is enough..

So if someone can get both measures working at the same time, please give me advice..    ..
No audio test in GSM is not working for me 

For _Wim_, basically no one RF Spectrum Analyzer accept DC voltage in input.. Remember that is has a 50ohm resistor in input, so more that aprox 5VDC burn the resistor... So if the equipment does not have DC block capacitor, as is the norm, you will have to supply one.

For ZL1CVD, yes all manuals are online.. so no problem to find how it works..

R&S have Windows programs in their web page to use the unit as tracking analyzer, and to make some GSM, WLAN, etc.. complicated measures.. (power, occuped bandwidth, etc).. You need serial cable o GPIB card and cable..

Regards
Manuel

[ZL1CVD]

That is good you have CMU200 now msraya

Mine has K29 which is just software. K29 need hardware CMU-B54 v14 which I have. I will see if i can figure out simultaneous RF & audio analysis.

I now have all manuals - user manual was not on R&S website nor could I locate it through google.

For windows software I am not looking to use GPIB. I would like to talk directly to the DLLs - for me Delphi or Lazarus would be the go as I'm not good with c. I suspect this may be beyond my abilities so may have to fall back to serial GPIB.

I'm in the processes of ordering a R&S CRTU-RU. It has windows loaded and looks loaded with RF cards. It certainly has the connectors for the I/Q output so I suspect (hope) CMU-B17 analog I/Q is fitted. This should allow me to play around with a an external Teensy SDR SSB/AM/CW modulator / demodulator. 

When _Wim_ asked about DC voltage I also thought ohms law which would mean on 2W input @ 50 ohms a max of 10V - unless of coarse there is a blocking cap which I'd have thought would adversely effect the frequency response?

Cheers for now!

[hoangviet]

Hi everybody

I just bought 3 dead CMU200 from a mobile company. They both had faulty PSUs but i manage to repair 2 of them which had issue with standby PSU, only faulty TOP200YN converter IC 

One unit had a Non-volatile Ram Empty error with Model CMU XXX and no Serial, work with only basic function, my guess would be the PSU fail at the time they update the firmware. In version manager i do see a choice to copy NVRAM to disk, but couldnt find the other way back 

The other unit work ok with all software option at start, but after few days the start-up process stuck at BaseDiscoverOptionsEnd with the Link LED in Digital Board blink sometime, i had trace the problem to the Digital Board by exchange with other unit but dont have any info to debug it. Anybody have the same error like this one ?

[_Wim_]

So if the equipment does not have DC block capacitor, as is the norm, you will have to supply one.

That was my question, does it have a DC-block capacitor? I currently use an external one (and an external attenuator if I do not know the signal level for sure), but as the unit is already quite deep, these screwed on attenuator are impractical and I would like to avoid them.

[_Wim_]

When _Wim_ asked about DC voltage I also thought ohms law which would mean on 2W input @ 50 ohms a max of 10V - unless of coarse there is a blocking cap which I'd have thought would adversely effect the frequency response?

As the CMU200 start only at 10Mhz, a DC blocking cap should not interfere with the frequency response if properly chosen...The 2 watts indicates a max 10V RMS signal or max 33 dbm (but not necessarily dc).

[msraya]

Yes, the blocking capacitor is a sensible theme..  Some spectrum analyzers get burned easily as the Tek 492.
For troubleshot RF circuits, I always use my HP85024A RF probe.  O0

I think is possible to use both functions: audio function and RF generator at the same time using GPIB programming.. but yet not try it.. I will post the info when I get it.

I need a macro o programing feature in the unit.. I will attach a PS2 Keyboard and press ALT-F4 to see what happens    I don't think The inside PC can be programmed directly in C or whatever.

I have the operator's manual and it includes all programing information, but it weighs 16Mbytes, please drop me a pm and I send you via email..

Manuel
 

[ZL1CVD]

Hi Manuel
I do have operating manual 1100.4903.12-06 thank you.

Alt-+F4 drops back to MSDOS. You can then run standard MSDOS programs. So anything you write with say old Turbo Pascal runs OK.

I tied to install Win98 and got through 1st decompressing & loading but it failed to boot into 2nd part of install - I didn't spend any time looking why. I had forgot to update BIOS with PNP OS and remove video caching which I recall from past caused 98 to hang on some machines. But I was also using a dodgy IBM 2.5" HDD. I'll wait until I get a CRTU-RU before spending any more time installing a windows OS. See what its running because its those DLLs I want to play with. Also the CRTU-RU has an either-net port. I'm hoping this is to the Win/DOS PC and not one of the RF cards. It'll speed up development if i can access file system via a NIC.

   O0
 

[msraya]

Ok, Thank You ZL1CVD for your comments..

I work in GPIB programming for a company, and although I don't have extensive experience in the matter, I don't have the time to play with the program inside the unit..
Long ago in the hacking games times, I run softice and cracked several programs in windows98, but nowadays my time is important to me and I have not the time nor patience to approach this issue.

I prefer to use a laptop or rasperry pi or similar board to automatize via GPIB the measures as noise figure, tracking, swr plots, Third order intercept, 1dB compression, and all the measures that interest me. The GPIB support of the unit is very good, extensive, as example you can access files from hard disk through GPIB calls.

However, if you make progress in the hacking I can support you by test or advice. You can transform a dll in a .h file to call from a programing language, but you will have only the entry points of the procedures inside the dll, not the information on parameters or functionality...  So, if you call the dll it can crash, and it will crash every time.

When I receive the new hard disk, i will see the innards of the file system..

I measured THD (as SINAD I cannot measure because my B41 unit has old firmware  ) on my 500MHz receiver with this little program:

*CLS
-> OUTP:STAT RF3
-> SOUR:RFG:FREQ 500 MHz
-> SOUR:RFG:MOD FM
-> SOUR:RFG:MOD:FM:FREQ 1KHZ
-> SOUR:RFG:MOD:FM:DEV 3KHZ
-> SOUR:RFG:LEV -40DBM
-> INIT:RFG;*OPC

-> CONF:AFAN:FILT:WEIG CCI
-> INIT:AFAN;*OPC
-> READ:AFAN?

So, the units can work at the same time.. no problem.. 

Update:  Works with python and VISA with Agilent usb<->gpib adapter, no problem..
I back up the Hard disk without problem. I see the dos app and found the version of the SW as 5.1 but the version of the audio FW is old 3.4.. It can be possible to update the firmware???  I think so.. It is detailed in the service manual as the board firmware must be updated after installation... I am not sure if I mess something..

Advice??

Manuel

[msraya]

The free software FreRes from Rohde & Schwarz allows to make sweep and test for example filters or duplexers.

Manuel

[_Wim_]

The free software FreRes from Rohde & Schwarz allows to make sweep and test for example filters or duplexers.

Manuel

Thanks for the tip. I seem to remember this did not work in the previous version I had. Lastest version can be downloaded here: https://www.rohde-schwarz.com/us/applications/freres-program-for-frequency-response-measurements-application-note_56280-15551.html

[richnormand]

Hi everybody

I just bought 3 dead CMU200 from a mobile company. They both had faulty PSUs but i manage to repair 2 of them which had issue with standby PSU, only faulty TOP200YN converter IC 

One unit had a Non-volatile Ram Empty error with Model CMU XXX and no Serial, work with only basic function, my guess would be the PSU fail at the time they update the firmware. In version manager i do see a choice to copy NVRAM to disk, but couldnt find the other way back 

The other unit work ok with all software option at start, but after few days the start-up process stuck at BaseDiscoverOptionsEnd with the Link LED in Digital Board blink sometime, i had trace the problem to the Digital Board by exchange with other unit but dont have any info to debug it. Anybody have the same error like this one ?

Hi hoangviet,

I seem to have a related issue with my CMU200. Although I think the standby supply is working and it is the secondary supplies that do not start. Either it does not get the power on signal or there is somthing wrong with the power-good signal. I removed all modules from the motherboard in case of a short, but, no luck.  Could you read my post and feedback any thoughts you might have. Since I do not have any pinouts on the plugs or schematics it will require lots of tracing, assuming the front control panel is not the cause.

https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

Anyone else with any experience fixing the CMU200 PSU here? Please chime in.

Cheers and thanks.
https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

[msraya]

Hello!

The HDD of my CMU200 is a HITACHI MK2018GAP with 20Gbytes but with only a 2GB partition  .
I try a KingSpeed SSD PATA 32GB with no luck.
Also I try a hgst 40GBytes ATA from my old laptop with no luck.
I think It is possible to enter the disk geometry manually in Bios, but I do not have information about the parameters of the disks.

But It appears that the BIOS is very OLD and doesn't read new hard disk..
I will try with a Compact Flash Adapter...

I would install Windows 2000, but I need a DB9 mouse  . I open the mainboard FRM5+8B version to see that It has a only 128MB module from a two sockets, the Intel 430TX Triton chipset must have some USB ports, but where are theses ports?

I will upgrade the memory. However, the old MSDOS Software uses Pharlap DOS Extender and DPMI mode, using only 64Mbytes.. so not interesting to upgrade RAM unless The Old software works under Windows, that I think that is not possible...

So.. please..  some advice...
Thank You!!

Manuel

[_Wim_]

Hello!

The HDD of my CMU200 is a HITACHI MK2018GAP with 20Gbytes but with only a 2GB partition  .
I try a KingSpeed SSD PATA 32GB with no luck.
Also I try a hgst 40GBytes ATA from my old laptop with no luck.
I think It is possible to enter the disk geometry manually in Bios, but I do not have information about the parameters of the disks.

But It appears that the BIOS is very OLD and doesn't read new hard disk..
I will try with a Compact Flash Adapter...

I would install Windows 2000, but I need a DB9 mouse  . I open the mainboard FRM5+8B version to see that It has a only 128MB module from a two sockets, the Intel 430TX Triton chipset must have some USB ports, but where are theses ports?

I will upgrade the memory. However, the old MSDOS Software uses Pharlap DOS Extender and DPMI mode, using only 64Mbytes.. so not interesting to upgrade RAM unless The Old software works under Windows, that I think that is not possible...

So.. please..  some advice...
Thank You!!

Manuel

See my previous post on this subject: https://www.eevblog.com/forum/repair/rs-cmu200-software-(firmware)/msg779471/#msg779471

My HD was also 20GB with 2GB partition, and replaced it with a 40GB one...

[msraya]

Thank You _Wim_ but The BIOS does'nt recognize the Hard Disk.. son I cannot make anything..
The screen freezzes in Detecting HDD Drive.... and I must make a hard reset.

It could be the BIOS versión, I don't know..
I have the backup file, no problem, thanks to your post, that I read before..

So, I must found an HDD that Works with that BIOS.. I need perhaps a HDD of no more than 8GBytes. A Compact Flash with adapter would be ideal..

Regards
Manuel

[_Wim_]

I also tried a compact flash with adaptor first, but had no luck with that. (I tried with this one: http://www.dx.com/p/sd-to-2-5-ide-adapter-card-227040)

[PartialDischarge]

First thing on arrival of the crtu I did make a security copy of the hdd with sucess. It uses a fujitsu 120Gb MHV2120AH, had to buy the same one, but I guess any iDE  hdd with higher capacity would have done it. I did a brute force copy ( with the dd commmand) from the hdd to my computer and back, the whole thing took 17 hours to complete!!!

edit:ide interface

[ZL1CVD]

I have backed up both CMU200 & CRTU-RU with the portable tool _Wim_ suggested http://hddguru.com/software/HDD-Raw-Copy-Tool/ 

Like _Wim_ I removed drive, attached to USB>IDE adapter (GL811E chipset - very old one I had lying around) to make the image. Takes around an hour or two and your done.

The HDD-Raw-Copy-Tool tool does a sector by sector copy of the entire drive. The resulting RAW image can be opened by a tool like PowerISO and this what I used to upgraded the CMU200 DOS software.

Both the CMU200 Celeron and CRTU-RU Pentium III boards have worked with various Fujitsu 20GB and IBM 30GB IDE drives I have connected.  BIOS has autodetected all OK. I have replaced the CMU200 drive with Kingspec PATA IDE 2.5" 32GB SSD and again HDD-Raw-Copy-Tool was used to write the image to the drive before installation. Now the CMU200 boots like a rocket.

I note the Award BIOS FLASH tool and bios image can be found in \internal\install\bios folder. Run the batch file FLASH.BAT to reflash.

Oh, and something I haven't done for years, plugged the IDE cable incorrectly and burnt out a power wire. Thought the CRTU-RU had smoked it was just the wire.  The SSD comes with same type of IDE cable - just longer. Put my glasses on this time when I reconnected it and everything ran fine.

Another tidbit - the Windows 2000 default password for user Administrator is blank on the CRTU-RU. Which is good as I haven't found a way to successfully boot from USB flash drive yet.
 

[dcarr]

The free software FreRes from Rohde & Schwarz allows to make sweep and test for example filters or duplexers.

Manuel

Hi Manuel,

Are you using RS232 or a GPIB adapter with FreRes?  Also, how fast is the sweep rate?

Thanks,
David

[msraya]

Hello dcarr:

I'm using a genuine Agilent GPIB <-> USB adapter and I don't have any problems. The CMU200 uses GPIB multiple addressing, so if you use a third party not full GPIB adapter you will have problems. The sweep rate is slow. You can forget to have real time sweep.. but it is working, and I think the precision is enough.
I will try to program my own software when I can..

Thanks, ZL1CVD, but I do not have folder bios... so I think your unit is newer... You can drop me the files, but I'm afraid to use the wrong bios image and convert my unit in an expensive paperweight. HI HI..

What happens if I use a image from another unit in my unit??  It can boot?  Or it needs proper serial numbers?? I will lost the calibration??  Someone Try this?? 

Manuel

[ZL1CVD]

From what I understand, calibration is stored in EEPROM on each R&S module installed. When you change a module, you run VersionManager (press menu/select key while DOS R&S boot screen shows). When VersionManager starts up, you then select "Firmware upgrade after board change" and this rebuilds what R&S refer to as 'tables' - I assume these 'tables' to be the module specific calibration data. 

I have connected the HDD from a CMU200 to a CRTU-RU and it booted up fine. I wanted to see if there were any options in the latest DOS software to handle switching in the B17 Analogue I/Q IF interface that is installed in my CRTU-RU. I could not find anything. I can only find a Windows application to control this. I'll read manuals more but suspect GPIB will have everything I need.

[msraya]

Thank You ZL1CVD for your advice! I made a Firmware Upgrade Change to try to upgrade the B41 firmware and It worked. But I cannot see any changes...

I update today the SW with the help of Wim and the Remote Service Tool..   When the update process finished, the unit not boot anymore..   

I get the HDD and when I put on PC I see that the data are destroyed.. so a faulty HDD perhaps... Then I write on it the backup version that I have and the unit come to life.. 

So.. no HDD faulty.. Wrong update process?? I don't know..
I want to update firmware for B41 option from 3.03 to upper level, for extract SINAD result by GPIB, but no luck... The software upgrade doesn't upgrade the internal B41 firmware 

When I receive another TOSHIBA HDD that I buyed I would try to upgrade again and install partition magic and a Windows 2000 partition.. I will need software for Windows 2000 that I doesn't have... If someone have?

If I success at it I will make a short tutorial of the process for all the CMU200 users over there.. 

By the way.. Someone knows how to use the Frontal Speaker with the B41 application???
I looked for GPIB commands or application options with no avail... 

Manuel

[hoangviet]

Hi hoangviet,

I seem to have a related issue with my CMU200. Although I think the standby supply is working and it is the secondary supplies that do not start. Either it does not get the power on signal or there is somthing wrong with the power-good signal. I removed all modules from the motherboard in case of a short, but, no luck.  Could you read my post and feedback any thoughts you might have. Since I do not have any pinouts on the plugs or schematics it will require lots of tracing, assuming the front control panel is not the cause.

https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

Anyone else with any experience fixing the CMU200 PSU here? Please chime in.

Cheers and thanks.
https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

Hi richnormand,
When i received my CMU200, the unit was totally dead, there was no LED light up when i plug in the power. Also i have another unit that does power on but the screen is dark. When i take a closer look at the LCD, i still see the image but the backlight is dead because of the inverter board which easy to repair. You should check your CMU200 by using a flashlight on the LCD, hope your unit have a same problem

[cio74]

Does anyone tried to use the spectrum below 10Mhz? Or/and power meter?

[ZL1CVD]

Minimum spec analyzer is 10.000005 MHz. I updated to latest 5.21 firmware and there was no change to this.

For power you set frequency and bandwidth (1MHz to 10Hz) and it displays it on graph in RF Power screen.


 

[richnormand]

Hi richnormand,
When i received my CMU200, the unit was totally dead, there was no LED light up when i plug in the power. Also i have another unit that does power on but the screen is dark. When i take a closer look at the LCD, i still see the image but the backlight is dead because of the inverter board which easy to repair. You should check your CMU200 by using a flashlight on the LCD, hope your unit have a same problem

Thanks for the clarification hoangviet.

In my case the amber/yellow light for standby does work. When I press the button it goes green. However there is no power out of the power supply at all. All the lines, except the standby 12V, are dead. So I have to conclude that my problem is in the PSU and was different than yours. There are more detail in the "repair" section of the forum.

Best of luck fixing the second unit back-light inverter.

[cio74]

Minimum spec analyzer is 10.000005 MHz. I updated to latest 5.21 firmware and there was no change to this.

For power you set frequency and bandwidth (1MHz to 10Hz) and it displays it on graph in RF Power screen.

Thanks, how much have you paid for yours? There are a couple on Ebay but I find the figure a little too high considering it does not cover below 10MHz (something that I need as a ham radio enthusiast).

[ZL1CVD]

I'm using mine for ham radio too. US$450 for CMU200 which has B95 (2nd RF gen). US$500 for CRTU-RU which was loaded B17 I/Q, 2x RF TX/RX, Etc. The CRTU-RU has no audio gen/analyzer. BTW the standard RF generator goes from 100KHz to 2.7GHz in these. The Spec analyzer is 10MHz to 2.7GHz.

I had an HP 8924 & Agilent E8285A. These R&S units are handy but do lack compared with these. Its mainly in the user interface and I think it is worth hacking around with that. In the mean time, there is 'some' usability there. If you want out of the box good old fashioned user interface that does analogue radio, get an 8924, E8285 or 8935. Unfortunately they are old and limited frequency wise but they do old fashioned radio really really well. The analogue duplex screen on these HP's is the 1st thing I want to try and emulate with the R&S's. 

[msraya]

Hello!

Frequency is not big deal.. Because you can use a coaxial mixer and have SA from 0 Mhz to 6 Ghz.. no problem...

The problem with the unit is that it needs calibration and that the sensibility and noise floor is not very good but sufficient...

This is not a clasic test set... but I think it is more for design and development than repair.. My Stabilock 4032 is more easy to work with and to make quick tests for repair...

I get mine for 900 euros with old mainboard, B17, B41 and B95. Not cheap but in good working condition.

Manuel

[cio74]

They look interesting, just not a lot of them available at the moment or I don't now where to look for them?

[Astrodev]

I know what you mean about 5 months ago there were quite a few around, if a bit pricey but they seem to have disappeared, it was just before this that I got my CMU200 and then when I got the chance of a number of CRTU's about a month latter I managed to get hold of 4 of these from an R&D lab that was closing down. But now even the CRTU's seem to be getting scarce.

As far as I understand there was a large number of CMU200's and CRTU's coming out of quite a few of the mobile phone manufacturers as they were not capable of handling the newer standards above 3G and so were no longer required, but I have also seen a large number of the CMW500's coming through which are still a current product as well as a lot of LTE gear from the likes of Anritsu.

So who knows what may start filtering through over the next year as the requirements evolve, it may well allow access to the sort of gear most of us could only dream of in the past at a price level the amateur can afford.

[msraya]

Hello All!!

I installed Windows 2000 on the unit, what a deception!!... It is so slow... I think it will not servers any purpose...
My LinkSys CF wifi 802.11b with CF adaptor doesn't work, I test 3 or 4 different drivers with no luck..
So no Windows2000 for me.. 

However the DOS software v5.10 works well in my new Hard Disk: 8GB CF Card with adaptor. 

So... I measure the phase noise performance of the set with my 10 MHz Rubidium Frequency Standard, a EFRATOM LPRO-101 Unit that is very nice, and has low phase noise.  I also build a simple ADE-1 Mixer to test if the unit can do Spectrum analysis from 0 MHz, with the internal generator and 1Ghz OL, and it work, of course... Although the ADE-1 is for no more than 500MHz, it works at 1GHz... outside of specs.. 

I put 7dBm @ 1GHz from the RF2 OUTPUT into the OL input of the mixer, a 30dB pad from the +10dBm EFRATOM source to the input IF of the mixer. And in the output (RF) of the mixer I connect directly to the CMU200 input. The spectrum is clean.

The trending on phase noise in my lab, from the poorer to the better:

RIGOL DSA-815 TG:   At 1Khz   -56dBc  @ 100Hz BW  (What a dissaster!!  )
TEKTRONIX 492BP:    At 1Khz   -69.6dBc @ 100Hz BW
RHODE & SCHWARZ   At 1Khz   With Mixer AD-1:  -72.5dBc  @ 100Hz BW
STABILOCK 4032:      At 1Khz   -76.2dBc @ 100Hz BW
RHODE & SCHWARZ   At 1Khz   -76.6dBc @ 100Hz BW

Manuel

[ZL1CVD]

Well Win2K on the CRTU works OK - not too slow. Would be better with SSD. But as others already mentioned, it does not play well when DOS firmware is not the same revision. Get lots of errors and most R&S apps refuse to work. Nothing really in Win2K worth having anyway - maybe the B17 IQ switching but you can get access to that in the latest DOS version I think...

[Astrodev]

But this is where the CRTU has advantages over the CMU200 as it already runs Windows 2000 and since most of the base functionality is the same unless you need the additional features that can be found on some of the CMU's (but this does depend on finding the right one) it may be a better alternative.

I suppose as they are fundamentally the same hardware platform the decision over which to use is really dependant on the hardware and license options present on the specific units that are available on the 2nd hand market.

My approach to running the CMU200 was to pick up a CMW-CU which is essentially a PC with built in GPIB and designed to keep RF interference to a minimum as it is specifically for use in an RF test environment and although it is for use with the CMW500 is works well with the CMU200 and the CRTU.

[ZL1CVD]

Just listed on eBay 182206586292 "CMU200 comprehensive measurement trace the source / diplexer tracking generator". How does this work? I know about wideband noise source but why the internal CMU200 connection? Does this provide an actual tracking generator taken from CMU200 spectrum analyzer LO output? 

[msraya]

Very interesting Thank You...
There is a output connector of LO1 sweep in the RXTX unit??? There are two free SMB connectors X36 and X35..
I will test it..

I would think the unit samples chunks of the sweep in the A/D and not useful at narrow BW
First IF RX at 1.816115 GHz? Yes.. in the service manual, the LO1 generates inside the RXTX Unit.

Board with amplifier+mixer for 100 US dollars?
If it works It would be Nice...   

I will think about it...
Manuel

[ZL1CVD]

.. and today we have another listing with better price on the tracking generator 252464888662..

[msraya]

I do not need Tracking, I have RIGOL TG...
But interesting.. for people that not have time to homebrew their own..  

Manuel

[Brainbox]

Hi to all readers.
I am new in this discussion and want to share some of my experiences with the CMU200.

Today I received the "CMU200 comprehensive measurement trace the source / diplexer tracking generator".
The unit came with the cables and connectors as shown on Ebay, but no additional information.
Better to say: no info at all.
The PCB has 5 MMICs, a mixer and some other less interesting stuff on board.
Since there is no information available where to find the LO1 signal I had to look for it myself.
The cable for this signal has 1 BNC bulkhead connector for mounting in a free hole in the back, and one straight MMCX connector.
Because the straight type connector makes it impossible to use X35 or X36 (The cover will not close) I was looking for an other free position.
When the metal plates from the RXTX cover are removed some holes shows up which expose some additional MMXC connectors.
Because I have no opportunity to measure this high signal I was looking an other way.
I had one RXTX board from a defective unit I removed the covers to see If I could find the right signal.
As it is the first local oscillator I was looking for the first MMCX connector I could find in the RX path.
Actually I found two two possible connectors after a split in the path.
I took some pictures to show what I mean.
As I don´t want to disassemble the good working CMU200 unnecessary I will take some time to prepare the setup.
When I know more I will let you know.
 

[msraya]

Thank You BrainBox for your review.

I buy also one piece of the kit.. But, I regret that I cannot test it yet...

The kit looks good... It has a double PIN attenuator to get the 0 dBm line right in manual fashion... 
I think it does not connect to the board surface connectors but the board edge connectors..

I not need manual nor information for use it.. It is very simple if you know how work a Spectrum Analyzer..
You can get The OL out from the RXTX board, simply firing the power meter and connect a frequency meter in the right connector until you found the correct frequency and level..

But I advise that this analyzer is only for experienced users.. That's Right 

Regards
Manuel

[bg7tbl]

i designed this board.now there is a new version .
for this board
power:DC 9-12V/0.33A
RF IN:connect to rx/tx board rx lo port.
P2:connect to front panel RF3 ,RF3 setting 1816.115M/-20DBM
IF OUT:TG output 10M-1.2G/0DBM.

any problem send email : bg7tbl@qq.com/BG7TBL@GMAIL.COM

[Brainbox]

Today I hooked up the tracking board to the RXTX unit.
At first I tried the free top MMCX socket X35.
That gave me some result, but only in fragmented parts as can be seen in the first picture.
After that try I decided to remove de side plates from the air ducts to make the internal MMCX sockets available.
Then putting in the connector in the a free socket (the one I had shown on the photo before) I got some better result.
This can be seen in the second picture showing a full span.
Unfortunately the level was not flat in the first 400 MHz or so but shows serious dips in that region.
Even so the picture is not stable but constantly jumping up and down, about once in every second.
Choosing a smaller span gives a much better result, but at low RBW the picture becomes jumpy again.
The last picture shows a 55 MHz lowpass filter.

Now I see they have made a new design with a RF can shielding. 

[Ericmax]

Hello everyone.

Having repaired the PSU and CPU Celeron 650, I bought a Pentium III CPU 933MHz CRTU with an old bios 0.9. (Bug in the time setting)
The DOS system CMU did not want to start. (CPU board incompatibility)
I made a backup of the bios FMR6 Celeron and I Flashed the Pentium FMR6 board.
FMR6 the Celeron and Pentium are the same, the CPU started without problem and the CMU works very well with the FMR6 Pentium 933 Mhz. 
if some have more recent BIOS than the 1.00 I am interested .

For backup and flash, i use awd789.exe . the last version of awdflash don't work with FMR6.

Good evening to all.

[bg7tbl]

reduce the wire connect or adjust the RF3 level can incresa the flat.

[msraya]

Hello All!!

I made test with the item...
I disasemble the CMU200 and then before installation the SA keep working.. no trace in screen.. 
It appears that the TXRX board is not settle in place.. Then It worked again 

So I put out the screening and Put the connector in place, only worked in the place that says Brainbox.
I put the BNC Bulkhead connector in the front plate in the Audio output conector. Then I put the Bulkhead of the audio signal in the rear panel of the unit.. No problems so far..

I put 12V at board and connect the board with little microwave sma cable.. I put 3dB pad after TG generator and adjust to obtain flat response. You can see in the photos...

Then I take a 10.7MHz crystal filter 25KHz BW i cannot remember...
You can measure about 20KHz BW..

It works a treat..    You can compare the trace with a Rigol TG.. The response is practically identical.
At 100 Hz the noise floor of the R&S is about -100 dBm..

The interface of the R&S is poorer than RIGOL, but it works..

P.D: I try to use 1916.2 MHz with the second internal generator to use the first generator at 100MHz with an input mixer and to sweep from 0 to 1.2GHz...  To test 455KHz Ceramic Filters...

BUT, It doesn't work because the BG7TBL design is using a filter post mixer that have a high frequency passband above 10MHz and the signal below 10MHz is greatly attenuated, so it doesn't appear in the screen....
I think also the mixer cannot work at these low frequency..

I would use a two mixer configuration to translate to 0 MHz..

Regards
Manuel

[Brainbox]

The second generator only goes to -60 dBm output power, probably that is too low for the mixer to give sufficient output ?
Indeed the BG7TBL design seems to cuts off from 10 MHz and beneath, but that is the same for the CMU itself.

Nevertheless; with this extension the CMU200 becomes of great value for me.

For frequencies beneath 10 MHz I do use an up-convertor which lift 0-10 MHz by 10 MHz to a useful 10-20 MHz.
Setting the RF generator to 1826.115 MHz in combination with this unit will give you a tracking extension in the 0-10MHz region.

I build the CMU together end mounted the bulkhead at a spare location at the back, the AF positions at the front are already used by the audio extension.
To place the air duct covers back in place I had to drill a hole in one of the plates.

[Ericmax]

Hi all.

small test with FreRes64 V5.25.
RF3 to RF1 and RF3 to RF2.
RF3 set 0dBm in FreRes.

10 to 2700Mhz step 10 Mhz.

RF3 out verified with my URV35 + NRV-Z6
i have same graphic of Rf power.

4dB difference from 10 to 2200 Mhz, may be a small problem on this CMU RF unit.   

[_Wim_]

Hi all.

small test with FreRes64 V5.25.
RF3 to RF1 and RF3 to RF2.
RF3 set 0dBm in FreRes.

10 to 2700Mhz step 10 Mhz.

RF3 out verified with my URV35 + NRV-Z6
i have same graphic of Rf power.

4dB difference from 10 to 2200 Mhz, may be a small problem on this CMU RF unit.   

Do you have the same result if you add some dwell time (to let the generator stabilize)? I can't test on mine right now, but will do when I am back at home.

[richnormand]

Just upgraded an 8924C for a CMU-200. It has a fault - internal RF loop path 1 test fails. Does anyone have any ideas where I should start? Also does anyone happen to have service manual with circuits - the one i have is missing all module exploded diagrams and circuits. Next step for me it to install a SSD. Cheers.

Going back to OPs question:

I have read through the entire thread and did not see if the issue had been resolved.

After fixing the PSU and the LCD display ( https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/  )  the unit passes all diagnostics tests except the internal RF loop and the 1->4 2->4 external loop.

Before going back in the box I wondered if this is a common problem that is well known in the community.

Cheers and thanks.

[w7owc]

I am considering buying this option for my CMU. Is there a practical way to mount this board inside the CMU200. Also how has the newer shielded board worked out?  I want this to sweep different cavity filters 30-1000 MHz? 

[Brainbox]

For me the option works well enough, I have the unshielded first version.
I don't bother about an exact calibrated output because I use it mainly for trimming filters.
Precise levels are not that important.

You can build the option inside the cabinet, I did consider that also.
There is a free 64 pole DIN connector on the main board inside where some supply voltages are available.
Mount the the option board on a adjacent adapter and plug it in the main board.
You can leave the LO cable from the RxTx board inside the cabinet en use  2 SMA > BNC cables to the backpanel to make the 1816.115 MHz and the Input available.

[oh2ftu]

The main problem with the unit is that it cannot make Audio analysis and RF analysis at the same time.. so I cannot adjust FM equipment with the RF generator and SINAD meter, nor I can use an external demodulator over the IF output and at the same time do deviation measures with the Audio analyzer.. 

I think I will need the AMPS extensions K29    and that must be purchased separately.. so only RF generator, selective Power meter, frequency counter, Spectrum analyzer, Audio Generator and SINAD meter for me is enough..

So if someone can get both measures working at the same time, please give me advice..    ..

I recently purchased (finally) my own CMU200. It's with FMR6, but PS/2 connectivity in the back.
The hardware options are B12, B21v14, B41, B52v14 and B54v14. Software options include K21-K24, K42, K43 and K45. Firmware version v5.1, v5.22 seems to be most recent.

My plan is to use this to tune radio equipment, but it seems I cannot analyze the audio that comes with the rf signal, is this true? Would the option K29 enable this?
I am able to modulate an audiosignal into the RF output, but cannot analyze it. Drat.

It still seems to be a lot to learn.

[danielg]

The free software FreRes from Rohde & Schwarz allows to make sweep and test for example filters or duplexers.

Manuel

Hi
I have an easy question regarding CMU200 and that is what is the best way to connect GPBI to Win7. I have access to serial port and parallel port (LPT) ?
Can I connect via LPT port or do I need some converter ?
I want to be able to connect FreRes because I hope I can use it to tune some duplexer.

Thanks for alot of useful information 

[msraya]

Hello!!

I want to be able to connect FreRes because I hope I can use it to tune some duplexer.

The LPT port is for printing only. And to transfer files in old MSDOS software.
The serial port works, but You must change secondary addressing for work with RF generator and audio analyzer at the fly. It is made by prefix the command with "1;" You can view it here: https://www.eevblog.com/forum/testgear/rohde-schwarz-crtu-gpib-control/

The CMU200 uses secondary GPIB addressing, so it behaves as three equipment at three GPIB addresses. One for system configuration, other for RF generator and other for Audio analyzer.. you can change it in the setup section.

So the easy connection is by GPIB with multiple addressing to configure. I use an Agilent GPIB to USB converter. I think freeres does not work with serial connection, but I don't know.

My plan is to use this to tune radio equipment, but it seems I cannot analyze the audio that comes with the rf signal, is this true? Would the option K29 enable this?

Yes, I think so.. But I cannot test K29 option. The receiver is SDR I/Q and in theory it has enough power by using a FPGA, so it would demodulate anything if you have the proper software. But it is more easy to use a external demodulator connected to the FI output. I use a Yaesu FT-817 with very good sensibility.

Manuel

[CJay]

I'm away from home now but I'm interested in the K29 option, my CMU200 has a few stickers inside which appear to be option serial numbers, what would K29 give me if it was present? (I have B54 which I believe is required to enable K29)

[oh2ftu]

Oh well. So I bought a second CMU200 (early, K6-2) with a dead (bright white) screen and K29 sticker on the back.
Boots with external display and the price was right.

I managed to fix the display by reseating the display flex, but broke the keyboard. It is now sorted tho!

About analog measurements;
To use as an analog service monitor you will need option K29 (AMPS), B21 signalling unit and B41 (audio analyzer). B54 is not required for AMPS.
Using AMPS will mangle you with a 30kHz stepping, but the offset is adjustable +-15kHz. It will show modulation and you will get demodulated output at the front.
Press the SETUP-button and check your options. The learning curve is quite steep, it's not near as easy to use as Anritsu MT8801B or similar - but you get _most_ of the functionality.

About Freres and R&SCommander. Neither will work over RS232. You'll need GPIB.

[CJay]

That answers one question, I need to obtain a suitable GPIB adapter from somewhere once I've checked which options I have available.

[danielg]

Hello!!

I want to be able to connect FreRes because I hope I can use it to tune some duplexer.

The LPT port is for printing only. And to transfer files in old MSDOS software.
The serial port works, but You must change secondary addressing for work with RF generator and audio analyzer at the fly. It is made by prefix the command with "1;" You can view it here: https://www.eevblog.com/forum/testgear/rohde-schwarz-crtu-gpib-control/

The CMU200 uses secondary GPIB addressing, so it behaves as three equipment at three GPIB addresses. One for system configuration, other for RF generator and other for Audio analyzer.. you can change it in the setup section.

So the easy connection is by GPIB with multiple addressing to configure. I use an Agilent GPIB to USB converter. I think freeres does not work with serial connection, but I don't know.

Thanks msraya for your help
Do you know what options I have to have enabled in CMU200 to communicate with GPBI and use that connecition to tune duplexer ?
Thanks

[msraya]

Danielg:

The generator and power meter both work at the same time in the MSDOS native app.
It is a basic functionality of the equipment, so you not need any special option for it to work.

The program FreRes will use both generator and power meter as same CMU200 unit at the same gpib address..

Manuel

[oh2ftu]

I did some tests last evening, mostly read through the Motorola professional series global tuner and tried out most of the alignment procedures.
In short, it's a PITA.
I recall seeing the power meter in AMPS showing power in watts, I'll have to figure this out (or just use a conversion).
Inserting rf input frequencies under amps really sucks. They must be input as Hz OR decimal MHz + offset in Hz.
If there's any chance in modifying the offset to 25kHz instead of 30kHz it would be superb.
On rx testing (AMPS RF gen) there's no option to enter discrete frequency - it has to be done with decimal MHz + offset in Hz.
I am opting to use both devices to get around the AMPS frequency input restrictions.
There are a dozen frequencies that need to be inputted in both RX and TX tests - for ~20 devices. So I will have to streamline it "a bit".

A note about the powermeter/frequency counter in normal power meter mode: The analyzer frequency and RBW must coincide with the signal for it to work.

I'm going to crossreference my devices when I get the GSPDO running; one has B11 and the other B12 so I hope they would be near each other.

[msraya]

Thank You!

I suppose that K29 not worth it. Only important for me is to adjust deviation on FM transmiter..
K29 have this measurement?

Another option is use a demodulator with a MC3361 and calibrate it in mV RMS with another modulation meter...

Manuel

[oh2ftu]

I suppose that K29 not worth it. Only important for me is to adjust deviation on FM transmiter..
K29 have this measurement?

K29 does show deviation; It is able to inject af signal at given freq to the DUT and analyze the received RF signal (power, deviation, freq error etc)

[msraya]

Interesting...

Now, only I have to find how to activate this option 

Manuel

[danielg]

Danielg:

The generator and power meter both work at the same time in the MSDOS native app.
It is a basic functionality of the equipment, so you not need any special option for it to work.

The program FreRes will use both generator and power meter as same CMU200 unit at the same gpib address..

Manuel

Hi
Little update, I have been searching for way to tune duplex filters by using CMU200. CMU200 is not offering or not licensed to sweep frequency’s so I have been searching for how to get the RF curve of filter. Last week I got Agilent 82357B that is USB to GPIB converter to connect my CMU200 to FreRes software. The short story is that worked very well and I want to say thank you for your help. I will attach pictures to give you and others an idea how gui looks.

Pic1 shows Rf cable looped from Generator to Analyzer
Pic2 shows duplexer. Red line is Duplexer Low input to antenna and black is Duplexer High input to antenna. Duplexer are for 158,1 and 162,7 Mhz.
Pic3 shows blue line as reference of -10 dBm output power from CMU200 in all tests. Black and Red lines are the same as in pic2
This test is done in three parts. FreRes allows you to seep multiple (this case three times) and draw pictures in different colors to compare.

I was wondering if anyone knows or have tested how to measure Reverse power and Forward power by using CMU200.
I’m trying to measure SWR of power going to duplex filter and back to CMU as part of figuring out if duplex tuning is ok.
At the moment I only know how to see power from generator and read it in analyser and I don't know if Reverse power measurement is possible - I the answere out there?   

Thanks
Daniel

[richnormand]

"At the moment I only know how to see power from generator and read it in analyser and I don't know if Reverse power measurement is possible - I the answere out there?"



Not sure exactly what your setup is but here goes.

I use a directional coupler with a -20dB tap to get the forward and, in a second sweep with the tap in the other direction, get the reflection measurement.
Generator (Tx) goes on one end and the load on the other (with proper matching if the load has an output of its own). The SA goes on the -20dB tap.
Then reverse the load and generator so the tap measures the reflected power and redo the sweep.

Works great with my HP SA cant see why it would not work with your CMU200 since you have access to the Tx Rx loop.

[danielg]

"At the moment I only know how to see power from generator and read it in analyser and I don't know if Reverse power measurement is possible - I the answere out there?"



Not sure exactly what your setup is but here goes.

I use a directional coupler with a -20dB tap to get the forward and, in a second sweep with the tap in the other direction, get the reflection measurement.
Generator (Tx) goes on one end and the load on the other (with proper matching if the load has an output of its own). The SA goes on the -20dB tap.
Then reverse the load and generator so the tap measures the reflected power and redo the sweep.

Works great with my HP SA cant see why it would not work with your CMU200 since you have access to the Tx Rx loop.

Hi, thanks for your input.
Do you recommend any type of directional coupler for 153-163 Mhz from ebay or aliexpress, could you point out some types please ??
Is circulator and directional coupler the same thing ?

Using generator that can give max -10 dBm out do you think -20 dBm output might be to much attenuate for such a low power to get realistic measure?

[richnormand]

@danielg,

I have three directional couplers. All three are Narda units, but they were bought from ebay for about $20 to 40 each at various times over the last 10-15 years.  You can find some for several hundred dollars but if you do an ebay search with "directional coupler"  many will show up at much lower prices, in particular if the paint is peeling or they have a few dents. Considering there are no moving parts and stout they are pretty rugged.

You can also find couplers with both forward and reflected taps on the same units. They seem to be more difficult to find though.

I have 0.5 to 2.0 GHz with -6dB tap, two 820 to 960 MHz with -30dB and -20dB taps and 225 to 460 MHz with-10dB tap.

If you are doing ratio measurements they will work quite a ways out of band too if you are careful. With the typical noise floor and dynamic range of the CMU200  (assuming it is working OK) I would not worry too much about a -20dB tap and -10dBm input.

[msraya]

Hi!

I have a MiniCircuits ZFDC-20-5-N N-Type 0.1 to 2000 Mhz ...
It is good to make swr measurements on antennas.

Manuel

[iz4beh]

Hello to all
a brief question about CMU200...
Spectrum analyzer , RF generator and power meter are optional or factory present in this instrument?
Many thanks

[_Wim_]

Hello to all
a brief question about CMU200...
Spectrum analyzer , RF generator and power meter are optional or factory present in this instrument?
Many thanks

As far as I know, these are always present. There can be some diffrences in the type op RF generator, but there is always one present. The following option (hardware) options are available:

B11:   HW-option for CMU200: Reference oscillator OXCO, aging 2 X 10E-7/year
B12:   HW-option for CMU200/300: Reference oscillator OXCO, aging 3.5x10E-8/year
B17:   HW-option for CMU200: IQ/IF interface, analog, one channel
B21:   HW option for CMU200: Universal signalling unit CMU-B21V14 incl. CMUB54
B21/2:   Universal Signalling Unit
B41:   HW-option for CMU200: Audio generator and analyzer
B52:   HW-option for CMU200: Speech codec for CMU-B21/var. 14
B52/2:   Speech Coder f. CMU-B21/2
B53:   HW-option for CMU200: Bluetooth extension for CMU-B21/var. 14
B53/2:   Signalling Module f.Bluetooth
B54:   HW-option for CMU200 signalling module for AMPS, TDMA, GSM for CMUB21/var. 14
B55:   Signalling Module f. €GPRS Applic. Test
B56:   HW-option for CMU200: WCDMA and data E2E for CMU-B21/var. 14
B66:   Versatile base band board
B83:   HW option for CMU200: CDMA2000 Signalling Unit (requires CMU-U65)
B85:   HW-option for CMU200: 8K/8K ENH/13K speech codec for CDMA2000 signalling unit CMU-B83/V12
B89:   HW option for CMU200: 1xEV-DO Signalling Module (requires CMU-B83/V22 and CMU-U65)
B68:   HW-option for CMU200 layer 1-board (3GPP/FDD, DL+UL)
B95:   HW-option for CMU200: Additional RF generator (max. input power 2 W)
B96:   HW-option for CMU200: Additional RF generator, 2 channels for GSM, CDMA, WCDMA

[ZL1CVD]

Where do I get / how to install VISA library. Installed FreRes but no visa library. Contenting to CRTU/CMU via RS232. 

New to SCPI. Got a Lazarus app to talk to my CRTU, reset it, display version. Yet to read data and do something with it. Was hoping I could learn from FreRes - see its commands...

[msraya]

Hi!

I installed VISA library from Keysight IO software because I have some Agilent gear and the library has an application to test the GPIB connection, drivers for the USB <-> GPIB adaptor, etc... The Keysight software can handle also the RS-232 port.

If you communicate via serial port with your CMU200, it does not support multiple addressing and therefore the FreeRes application doesn't work. I think you need a real GPIB connection to use multiple addressing vía gpib32.dll.

The Keysight IO library is heavy, some 120MBytes or more... you can download it from Keysight website.
For the FreeRes app you only need the USB-GPIB drivers and the gpib32.dll in your system.. But Keysight IO assistant is helpful for troubleshooting the connection. And a heavy installation.. 

FreeRes is not very powerful... It is more interesting to program a visual application in phyton that manages the unit via GPIB and can use several instruments at once, this cannot be done from the front panel of the unit, but throuth GPIB you can use the power meter, generator, audio test all units at once..  I have no time to do it... but perhaps someone have time to do it... 

Manuel

[ZL1CVD]

Thanks msraya. I'll skip that for now. Cant really afford more adapters at moment so will use serial for now.

Just managed to read data from CRTU and write to a memo - wahoo! Now to see if I can get the app to send user data from an edit, spin edit, list, etc. Then I'll see if I can populate a tree with the result of system:options?

this is fun ...

[msraya]

Your welcome!

The CMU200 is a great piece of kit. GPIB expand the instrument.

It has a user calibration table that you can edit and send through GPIB. So you can calibrate the equipment with a good meter and keep user calibration in the unit. You can also use several user calibrations to test for example Noise Generator for tracking, Test Antennas, GHz converters, etc.. With some imagination you can use it for several uses..

I am right now working in another endeavour, HI HI.. but I would write software for the instrument if I need it...
Regards

Manuel

[ZL1CVD]

Does anyone know the secondary GPIB address for the 2nd RF channel (RX/TX Board 2) in CRTU-RU?

I want to be able to control the RX/TX Board 2 via SCPI

I know secondary GPIB address's can be changed on the CRTU in Setup>>Remote>>Secondary Address [GPIB] screen. However it only shows 1 RF device.

SYST:REM:ADDR:SEC? only reports 1x RF_NSig.

The CRTU-RU documentation doesn't seem to cover SCPI commands which is not surprising as I suspect its mainly addressed directly via Win2K. when you boot in DOS mode, it basically reverts back to a CMU200. I have a CMU200 & CRTU & can't see any difference between CMU200 & CRTU DOS file systems for SCPI remote control.

[ZL1CVD]

** RF loop path 1 test failed - FIXED **
Was a faulty power supply. This same power supply would also not start up from standby *sometimes*.
At some point, the CMU had been dropped on the, you guessed it, power supply - it was pushed into the case - housing dented. I have seen the same thing with an older K6 CMU (with PS/2 keyboard port). These older units are much more forgiving for case / transit damage as their motherboard does not go completely to the rear of the case like the newer Celeron CMU or Pentium CRTU units. The rear connections are made via ribbon cable to separate rear PCB strip. I was very lucky that there was no PCB damage on this newer Celeron unit.
Now to figure what pins have what voltage and see if I can find the cracked joint...

[richnormand]

** RF loop path 1 test failed - FIXED **

Now to figure what pins have what voltage and see if I can find the cracked joint...

If you are talking about the PSU used in the CMU200 and such look up my thread on CMU200 PSU repair from last year. It has full pinout of the connectors and several diagrams. Hope it helps you.
https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

[CJay]

Bear with me, GPIB newby here...

I've managed to get hold of a PCI GPIB card, cabling and have got my CMU200 to talk to FRERES on Win 10, could someone please show me some screenshots of how you configured it to sweep a filter, complete with devices setting and sweep setting as well as the main FRERES screen?

I'm positive it's something simple I just haven't got a grip on yet but I can't work it out.

CMU is set up for SCPI via GPIB only
Primary address 28
Secondary has RF Non Signalling on address 1

Running a sweep seems to work but the data FRERES displays is noise at -86dBm, regardless of how I loop the RF ports on the CMU.

As I said, it's something simple but I just can't see what I'm doing wrong.

[usagi]

what DANL are people seeing with their cmu200?

[ZL1CVD]

..up to -100 - depends on setting, input port, etc...

Same for both CMU-RTU and CMU-200

[ZL1CVD]

Better than -130 with span less than 1MHz & RBW 500Hz or less..

[NavyBOFH]

I have seen the posts about the eBay link for the tracking generator add-on someone created - but has anyone given some real use and performance on it? I would like to know if it comes close to the other service monitors and spectrum analyzers I have used.


Sent from my iPhone using Tapatalk

[Brainbox]

I own one and for me it does what I expect from it.
But how by heaven can I tell You if its meets the specs of Your other service monitors?

[richnormand]

I have seen those, and opted for a different option that does not require opening up the modules and the CMU200.

I got one of the $25 eBay noise source from 1MHz to 3.5GHz. They are not all that flat but are handy for quick measurements. For example here are pics of my HP8561E with it's tracking generator HP84640A looking at the response of a lithium niobate SAW device. The other picture is the CMU200 using the noise source with the same device (but... do note the different dB/div and span between the two photos).

Quick and dirty but it works. All depends of what you want.

[_Wim_]

For measuring the frequency responce, you also can use the FreRes software (https://www.rohde-schwarz.com/uk/applications/freres-program-for-frequency-response-measurements-application-note_56280-15551.html) where the generator and analyser are configured for as many frequency points as you want. You can get a very high resolution read-out, but that takes a long time. But still, very usefull.

[usagi]

i love my cmu200, the only downsides are no preamplifier option, and it only goes down to 10mhz.

it has a great signal generator, and with freeres i even have a poor man's tracking generator.

for what i paid for it, it's a phenomenal value.

[CJay]

i love my cmu200, the only downsides are no preamplifier option, and it only goes down to 10mhz.

it has a great signal generator, and with freeres i even have a poor man's tracking generator.

for what i paid for it, it's a phenomenal value.

I'm rather keen on mine too, I've been tinkering with using one of the RF generator outputs as a LO for an external ADE-1 mixer, yet to quantify results but it seems to work.

I am having problems getting results from FreeRes though, I'd be grateful for any tips on configuration of the CMU and PC?

[Brainbox]

I have both the tracking generator and the noise generator.
From those I prefer the tracking generator for its broader band.
The noise generator only have a satisfaction output in a small band.
Higher the bandwidth  decrease the output level ans also the resolution.
But it can be useful for preselection purpose.
FreRes also is a great solution but requires the use of a external PC.

[Octane]

Hi,

I'm looking into buying a CMU200. But I'd like to know a few things.
Can the built in generator do FM, AM, or any other analog modulation types?
Can any of the analog modulation types be analyzed/demodulates?

I tried to find general info on the CMU200, but I could only find documentation on for example how to do GSM measurements.
No general manual or any other information.

Thanks,
Michael

[Brainbox]

Yes it can do most types of modulation for measuring purposes.
Do a search at Google for the user manual and service manual, you will find all the specs You need.

[Octane]

Thanks Brainbox,

That's what I wanted to know. And yes I googled for the manuals, but I was not lucky yet. I'll keep trying!

BR,
Michael

[usagi]

Can the built in generator do FM, AM, or any other analog modulation types?

yes, it can do FM, AM, SSB, DSB, CW

Can any of the analog modulation types be analyzed/demodulates?

yes, but you have to get a cmu200 with the correct options.

[ps]

One question concerning RF ports 1 and 2: these can be input and output at the same time.

Is there a directional coupler present, i.e if I use the signal generator to drive an antenna, do I measure the returned power (S11)?  Or does it just measure the voltage and calculates some kind of equivalent power assuming a 50 Ohm load?

This is not clear from the block diagram in the service manual.


Thank you, best regards
Patrick

[Octane]

As far as I understand this it is either/or not and. There is no directional coupler inside. Please correct me if I'm wrong.

Michael

[usagi]

cmu200 has no directional coupler.

took me a while to figure out how to do RL with freeres. if i remember you have to use RF3 out with RF1 in.

[Ringmodulator]

Hi,

for my understanding, the CMU-B95 ADDITIONAL RF GENERATOR limits the max RF input to 2W.

 Is it sufficient to remove this unit, to be able to use the full RF input of 50W, or do I need some kind of "jumper cable" to bridge the connections of the removed board?

Chris

[RF_fanatic]

Yes, use AMPS option of the CMU and the audio output which can be attached to any audio input of a normal amplifier and you can use it as tuner (fm demodulated)

[cmu2017]

Hi,

I would place my tracing generator into the CMU. So does anyone know if there is somewhere 12v inside available? And it would be nice if this 12v can be switch on and off by one of the (function) keys on the front.

Does anyone know if this is possible?

[Qw3rtzuiop]

There are two 12V rails inside. One is always present (12V standy). The other rail is available on power up. Afaik there is no switchable rail.

[cmu2017]

Too bad that there is no switchable 12v. Have you maybe a photo or something else to see where I can find that 12v?

[Qw3rtzuiop]

You can take a look at the service manual. There are the connector descriptions. The 12V should be present at almost any of the big connectors at the main pcb.

Edit:
Here is the spare parts list with the connector descriptions:
http://www3.rohde-schwarz.com/www/FileTranCS.nsf/4073a08b63359686c1256ae6002f8239/0b37697a081fa22ec1257834002005ed/$FILE/Shb-inst_Documents.pdf
Its not in the service manual.

[cmu2017]

Thanks, I found it.

[cmu2017]

Does anyone have the print design of the motherboard? I want to cut some small part of the corner. So I can place a new rivet nut for the leg. But I need to be sure there is no circuit on that place. (See image)

[cmu2017]

I’m using the cmu200 now for a while and I have a few questions about it which I couldn’t find on the manual.

- Is it possible to set a ref -> pk  to a negative peak
- Can I change the power measure form dbm to watt
- Is it possible to make a print screen save it a usb stick

[PartialDischarge]

- Is it possible to make a print screen save it a usb stick

In my CRTU I bought a PCMCIA to SD adapter to make screen dumps, but all attempts with different card sizes have been unsuccessful, although someone told me it worked in his unit.

[capt bullshot]

In my CRTU I bought a PCMCIA to SD adapter to make screen dumps, but all attempts with different card sizes have been unsuccessful, although someone told me it worked in his unit.

I did successfully install additional FW modules on my CMU200 (old CPU board w/o USB) using a PCMCIA to CF adaptor.
Never investigated how to make screenshots onto this CF card, would be interesting to get some hints ...
What I'm really looking for would be some simple linux software that connects via RS232 / GPIB to the CMU200 and takes the screenshot by running a simple binary on the PC - hardcore command line style, no clickety GUI.

[cmu2017]

In my CRTU I bought a PCMCIA to SD adapter to make screen dumps, but all attempts with different card sizes have been unsuccessful, although someone told me it worked in his unit.

What button’s do you use to make screencopy and how get it to the PCMCIA card? And are running for this on dos or windows. I’m using the dos modus.

[PartialDischarge]

What button’s do you use to make screencopy and how get it to the PCMCIA card?

PRINT IIRC, there was an option to change the destination of the print somewhere, either to the HDD or the external memory through pcmcia

[cmu2017]

Ok, thanks, I'm going to try this.

[Bicurico]

Perhaps this may interest you guys: http://vma-satellite.blogspot.pt/2018/03/vma-simple-spectrum-analyser-for-crtu.html

Regards,
Vitor

[richnormand]

Just downloaded.
Can't wait to try it.
Thanks for the work Vitor.

[CJay]

It does and I've downloaded copy but have yet to find time to hook everything up.

Looks very impressive though

[Bicurico]

Some info:

This is still the first version and there are some bugs, obviously. Also, I want to increase the functionality. Unfortunately I have had zero time for my hobbies in the past weeks.

In order to get the software working, the following is needed:

- CMU200 or CRTU with firmware v5.20 if serial connection is to be used - not tested with older firmware releases, but it seems that only v5.xx offers 115200 baud
- Keysight Connection Expert 2018: some users reported that it doesn't run with older versions. I don't know, because I only tried this version.
- Recommened: Agilent GPIB/USB interface (I ordered a "refurbished" one from China through eBay and it cost me around 80 Euro plus 60 Euro for customs).
- You need to setup remote connection on the CMU200/CRTU: test it with Keysight Connection Expert 2018. If it works here, it should work with my software.
- To run my software, you need a (free) activation code.

Regards,
Vitor

[ps]

- Is it possible to set a ref -> pk  to a negative peak
- Can I change the power measure form dbm to watt

Check the list of GPIB commands. There are a couple of funtions and settings that are not accesible with the front panel controls. If it isn't there, it is not possible.

- Is it possible to make a print screen save it a usb stick

No. MS-DOS does not support any USB at all. There is a USB to PS/2 keyboard emulation in the BIOS, therefore an USB keyboard will work, but that is the only device type supported.

[CJay]

I have the Keysight 2017 software suite on a PCI based PC with a PCI GPIB card, I'm hopeful it will work with that.

CMU Base is 5.21

I'll dig out the PC and cables one evening next week and request a code, thank you for all your hard work.

[cmu2017]

Thanks all for your answers.

@Vitor
Looks great :-)
But do I need also OPSW v5.x installed? You have this mention on your blog. But not here on your post

[Bicurico]

OPSW v5.x is the DOS Software that runs on the CMU200 and CRTU.

I noticed that v3.x has only baud rates up o 19200, which is much too slow.
With v5.x you get 115200 baud, which is slow, but works.

Using the GPIB/USB interface you get 1.5MBit/s and thus you get a pretty fast refresh rate on the PC.

Regards,
Vitor

[stan33]

Hi,
I have just bought one CMU200 that I will use using SCPI commands through the serial port only.
I have some troubles to use is as as simple spectrum analyzer. Is there a simple SCPI command sequence  to:
- set the display in max hold
- make a peak search and measure peak level/frequency ?
I am interested in doing this without getting arrays (if possible).
Thanks is someone can help.
Stan

[markus_jlrb]

Stan,

you have to look for R&S doc for the CMU200
https://www.rohde-schwarz.com/de/suche_63238.html?term=cmu200

The remore seq. is looking like that one below:

set remote command mod. via menu ant then
send via RS232

1;INITiate:SPECtrum
...
sorry but for the middle part I have no example.
...

send to go back local mode
1;*GTL

Markus

PS.: There is a free software to control the cmu, you have to ask google.

[stan33]

Hi Markus,
thanks for your help. I can set a lot of things using scpi, unfortunately I did not found any scpi commands for:
- setting the display in max hold
- make a peak search and return peak level/frequency
I can do this using the UI but not using scpi commands.

[zitt]

I picked up one of these boat anchors off of TheBay about 3wks ago. I just replaced the Fujitsu Rotational HD with a PATA SSD because... well; I'm paranoid that 15year rotational drive is suspect at best.

That said; I made a backup of the hard drive "in case"... and it appears to be running base3.22 of the application under DOS 6.22.
I tried almost successfully to "upgrade" the system to FreeDOS 1.2... but there was some kind of batchfile strangeness with the version manager that the software wouldn't start so I gave up.

I'm thinking about upgrading the the latest and greatest application/firmware. I've seen some have posted here and there is at least one utube video of someone doing it. Has anyone done it recently? Any advice to give to help quell the FUD I have?
If the update fails; can I just re-image the HD with my old copy and be up and running? or does the upgrade process really program eeproms?

[ZL1CVD]

Yes firmware upgrades EEPROMS aplenty& the firmware upgrade / downgrade process has no problems going back or forward revisions. If yours has an AMD CPU, older motherboard & older modules v5.1 is probably the latest you will be able to run. Trying 5.21 wont kill it but you may find some features disappear - from memory, an old one I worked on lost Audio. Make sure you use version manager to install new firmware and do not just copy & move folders which I was initially doing. Version manager does some sort of voodoo to make everything work.

[zitt]

My device:
AMD K6-III
CPU (FMR)       FMR5
Memory         192 MB
BSW/FSW         V3.22

[_Wim_]

I can do this using the UI but not using scpi commands.

That will probably be the way to go...

[Kribok]

Hello to everyone and sorry for poor English.
Encouraged by the possibilities and low price of the CMU 200, I bought it for around 900 $ with a view to using it in radioamateur measurements (spectrum analyzer + RF generator). After one week of use, the RF generator stopped working. I was looking for information about the fault, but I found nothing interesting. At the time when I want to turn on the FR generator, the device hangs and the buttons do not work, I need to turn off the CMU 200 to work again. If anyone has any interesting proposals for repair then I will be grateful. I will take photos and a more detailed description of this fault soon.
I greet everyone

[ZL1CVD]

Check the two 50 way cables W223 & W224 are firmly in place - these connect motherboard A200 to motherboard 2 A201. Quite common for W224 to come loose. Also check 34 way cable from front end module A20 to motherboard A200. Also look at the software version number when it starts up. If it says 5.21! and not 5.21, then there was a problem with the DOS software installation and you should reinstall. Choosing "firmware update after board change" in VERM can sometimes also clear the problem. Finally, a faulty digital unit A7 has been known to cause this issue. Re-seating the board may work also pulling it apart, removing the sub modules and giving it a good clean also works. 73s om de chris zl1cvd.

[Kribok]

Thank you very much for the hints and interest in my problem.
I unscrewed the CMU 200 to check the connections and took out the RX / TX module, just like my colleague had previously said about cleaning, the whole module was heavily soiled, I took out all the modules in turn and cleaned, including the control module and the fan duct.
I took pictures, and I'm working on putting them in this forum - I'm sorry I'm a novice.

[TheDefpom]

I thought I might was well post these here for reference, it might be helpful to someone.

[Kribok]

If someone buys such a device second-hand, it is worth to unscrew and clean them, just like your friends suggest.
I attach a few photos of the condition of the device.

[Ice-Tea]

That's terrible. Never seen anything like it.

[Kribok]

Unfortunately, it looked like it is now clean.
Thanks to the suggestions of my friend ZL1CVD, whom I thank, my CMU 200 is like new, I cleaned all modules and connection pins.
Earlier, a message about too high temperature appeared a few times, now the CMU 200 is on for a few hours, and it's great.
Unfortunately, after turning on the RF generator, the device keeps crashing.
I searched for information on the internet and found something like this -
https://www.mikrocontroller.net/attachment/338050/CMU_BASE.INI.TXT
I do not know about programming, but maybe someone will be interested.
On the Rodhe & Schwarz website I found this -
https://www.rohde-schwarz.com/pl/software/cmu200/
My software is SW V4.35!
If it is a software error like ZL1CVD wrote, then where can you get newer software, because on the company website Rodhe & Schwarz is probably older than I have in my CMU200, but I can be wrong.
I'll do some more photos.
I greet you all.
I have been subscribing to DheDefpom's friend channel for several years, and have watched the videos several times.

[Ice-Tea]

I have a complete copy of a CMU drive here somewhere, probably with more recent SW if you want.

You can also go in the service menu during boot, indicate you changed boards and the SW will rebuild. May be enough to save your day

[Qw3rtzuiop]

You can find the latest software here:
http://gotroot.ca/cmu200/
Extract the files to a memory card and insert it in your device. Press "Menu Select" at startup to get into the boot menu.
Then you can update all the software packages.

[usagi]

That's terrible. Never seen anything like it.

looks exactly like some cisco routers we got off ebay a long time ago. they were used in a porn shop where everyone heavily smoked cigars. the insides were furry just like the pictures in this thread.

[Kribok]

With my little experience with CMU 200, I will first see the reinstallation of the software, because it will probably be easier. Thank you for the instructions, I'm reading them.
In my CMU 200, from the moment the ON button is turned on, it takes about 8 minutes to fully standby. After activating the spectrum analyzer, it works normally, you can change the values of the RF generator, but when you turn on the RF ON generator, the entire CMU is suspended.
When I bought it, it worked normally and quickly turned on, after a week of use something changed.
In the middle of the module located closest to the power supply, on one of the tiles I found such a button?

[Kribok]

At the beginning, the CMU worked normally, after a week of its purchase, the RF generator stopped working and a message appeared - photo 01
In my CMU, such modules are installed - picture 02
Since the appearance of this board, about 8 minutes will pass until full launch - picture 03 - 04
After starting the self test, the CMU hangs on the '' Diagnostic CMU -B56 Var14 '' message - photo 05
I made a reinstallation - photo 06
After starting the system a message appeared - photo 07
I turned off and turned on the CMU 200, after restarting the system (as before 8 minutes) the RF generator does not work.
I am looking for information on error codes, but it is probably only Rohde & Schwarz who has access to them?
If it is the fault of the software, then with the help of colleagues, you can try to fix it, and if it is a malfunction of a module, then only the replacement of it comes into play. After cleaning the modules, I saw how complicated the CMU is and why the price of the new device is so high. In the radioamateur studio, we can use the spectrum analyzer and RF generator for our home tests if you can buy a second-hand CMU at an affordable price.
I am very happy to hear the proposals on how to repair my CMU!

[_Wim_]

Disclaimer first: I am no specialist of the CMU200, just looking at the service manual (http://gotroot.ca/cmu200/CMU_Service.pdf)

Option CMU-B56- appears to be a plug-in module of the signalling card (B21):

Option POWER PC
R&S CMU-B56 Var14
The option POWER PC R&S CMU-B56 Var14 is directly inserted on
the UNIV. SIGN. UNIT. It performs WCDMA signaling function.

So would it not be possible to remove this option module only? My CMU does not have one, but still the signal generator can be used.

According to the above service manual, this module should have the following number:

1122.9737.22

EE POWER QUICC II MODUL 
POWER QUICC II MODUL
included in CMU-B56/MOD14

So if you open up the B21 module, I would remove the module labeled with "1122.9737.22", but as stated above, I say this from only looking at the manual, no real experience in doing this. 

[Qw3rtzuiop]

You didnt update the firmware. It is still an old version. The newest should look like this:

[Kribok]

Yes, I did not want to change the software, just verify it, as my colleagues suggested.
I take all the hints into account, because I do not know about programming, if I need it I will buy a PCMCIA module and I will make the software update to the latest one.
All hints and suggestions are very welcome.
Thank you very much .

[Kribok]

I wanted to do a reinstallation of the software, and found the disk defragmentation, like in a computer.
During the defragmentation, such a message appeared - photo 1
The CMU has hung up, and after switching it back on, it now shows such a message - picture 2
I sat for a whole day and wanted to turn on the CMU and it always hangs and shows the message - picture 2
Nothing else shows and nothing can be turned on.
I think it's just left, reload the new program.

[CJay]

Yeah, the hard disk is corrupt and possibly/probably faulty, you need to get that replaced and reloaded, I'd recommend replacing it with either a CF card in a CF-IDE converter or an SSD if you can find a PATA one but the BIOS on some of the CMU200s doesn't have great support for newer hard disks so you may need to experiment a little.

[Bicurico]

You will need a backup image of a working CMU200 (sorry, I can't help you, as I have a CRTU).

Hopefully you have one, if not this is a good time to ask other forum members to upload such an image.

For me, it turned out that the "dd" command under Linux or Windows is the best way to read/write such an image.

You can for instance hook up the new replacement disk with an USB adapter to your Linux/Windows computer and then use the "dd" command.

Your error appeared because your HDD is broken and scandisk moved some firmware binaries to the broken sectors. Bad luck.

Regards,
Vitor

[CJay]

I do have a new CMU200 hard disk which contains the base software, I'd happily sell it for what I paid (£20) and delivery you'd need to reload the later versions of the software and re-enter your option keys but that's pretty easy to do, there are links in the forum to the later software versions.

[Kribok]

I am happy to buy a hard drive for CMU, but it will be a problem to re-program it. I can pay for its programming, so that I can mount it in the device (linux - dd, it's magic for me).
Greetings

[drew23]

Hi. I have two CMU200. You may be able to resurrect your HDD by connecting a keyboard and booting to MS-DOS at startup. From there you can do a scandisk to fix any problems. I had a HDD error with one of my machines and that fixed it.

It is a good idea to make a DVD image of the HDD as soon as you get it. Similarly, not a bad idea to use a new HDD. They often have done huge hours as they are often left on.

I had trouble finding a SSD that would work with it. Does anyone know of a parallel SSD that is recognised? It may be a BIOS issue, as I have not upgraded mine.

Regards Drew

[markus_jlrb]

@Kribok,

have sent you a PN.

Markus

[Kribok]

Thank you very much for your interest and hints, I am at the HDD gathering stage, PCMCIA interface, and other ...
I will share everything with my experiences and achievements.
Once again, thank you all and all greetings.

[Wilts01]

Does anyone know if it is possible to use the audio output at the same time as the RF functions?  I have a CMU200 with the audio card and would like to use it to output an AF sine wave at the same time as viewing the Power/Time RF display?  At the moment, once I have setup the audio output, as soon as I go up the menus to the RF analyser/generator option to the Power/Time display, the AF stops.

Thanks

Paul

[Qw3rtzuiop]

Somebody asked the same question in the mikrocontroller.net forum. There wasnt a solution for that problem. I tried it myself but i cant get it to work.

[Ice-Tea]

Just a thought... GPIB?

[xmo]

I believe the audio and RF functions can be active concurrently if you have option K29 (AMPS).

[usagi]

any recommendations for SSD that will work with FMR5? Is CF-PATA the only option?

[lordium]

I have the FMR6 version, so not 100% relevant, but I got it working with a "RunCore 4GB SSD" that I got the cheap on the interwebs. Used dd to copy from old HDD (with a ide-to-usb adapter) and it works fine. Did this after my HDD in it starting clicking in a funny way.

[Torkrench]

I'm not sure if this is the correct place to ask this, but I just picked up a CMU200 today.  I thought that the internal speaker would allow me to hear audio frequencies when in the AF analyzer option.  I get no sound from mine at all.  It does have the B41 hardware option and the coax cable from the speaker is connected.  Is there a button or setting I'm not aware of to turn on monitoring?  The VOL button doesn't appear to do anything.

[Kribok]

Hello ! a few hours using CMU and testing in turn, and R & S suspended during testing and needs to be turned off and on again -
Internal RF Loop Path
1-> 4 / 3-> 2 RF Loop Path
FM Modulation Calibration
L1CoPro Level Calibration
Internal AuxTxLoop Path 1
IF3 Selftest
Settle Time Calibration
The remaining tests are performed without problems, and the spectrum analyzer and audio tester continue to work, but when the RF generator is switched on, the CMU suspended.

[Kribok]

Happy New Year 2019

[Kribok]

Hey .
One of my colleagues was so kind that he came to me with his CMU and we could check his devices. After a few hours, replacing almost everything that was possible, it turned out that the tile shown in the picture is damaged. After removing this plate, my CMU turns on normally, i.e. very fast, but the RF generator still does not work.
With an efficient PCB, the CMU operates normally and also an RF generator. Question for 100 points, which is most often damaged?
We are not able to locate the damaged component on this board. I want to thank everyone for all the help and all the hints, and of course my friend for taking the time to diagnose the fault. I greet everyone.

[Ice-Tea]

Where does that piece come from? I may well have a spare for that but I don't recognise it..

[Kribok]

From what has been set at 100%, this PCB is damaged, which is placed in this module - pictures.
If someone is more experienced in repairing the CMU 200, or knows what is most often damaged, then I am asking for a hint, or if someone has such an efficient board, I will gladly buy it back!

[Qw3rtzuiop]

Hello,

R&S calls it the TXDSP MODULE. So it is plausible that your generator didn't work.

I have a spare broken DIG board that contains this module. I had rx problems with that board. The tx worked fine. But you have the newer version 1100.2130.03. The one at mine is the older 1100.2100.03.
I don't know if they are compatible.

[Ice-Tea]

I'll check if I have the right version somewhere.

[Kribok]

This small PCB is damaged at 100%, because after replacing it with another CMU it works normally. Thank you for your answer, and I will gladly buy back such an efficient one, of course if someone has such a plate for sale. Possibly any suggestions, what usually goes bad on these PCBs, if someone has already repaired it?

[Kribok]

This is the PCB that is damaged - the smaller one with the inscription in the middle of the DIG. In the pictures I showed the connectors. I do not know if there are any other versions of this tile, but after converting it to another, the CMU worked normally. During the test I did not even check the subtitles on this board, because it looked similar and when it was put in its place it worked normally. I do not know if there are other versions of this PCB that may not work in my CMU, if anyone knows something about it, please write. I greet everyone

[Ice-Tea]

Got one

[Qw3rtzuiop]

The soldering at the yellow tantalum cap looks sketchy.

[Kribok]

I checked this with a multimeter, and it turned out that there is a short circuit, just like you, I thought it was a tantalum capacitor, but after desoldering the PCB did not work, as before. The colleague dismantled this PCB from his CMU and soldered it something, because it also showed a short circuit, but the PCB was working and working in CMU, it turned out that it has an inductance, i.e. a choke! That's why I sold it back to my PCB.
Greetings.

[Ivan_Vetrov]

Hello! How to make a calibration after replacing the hard drive? I now have the level of the generator from the level of the analyzer differs by 3 dB. When the generator level is set to -27 dB, the analyzer level is -30 dB. The D-Line marker shows -22 db. What do I need to do to calibrate?  Thank .

[Kribok]

Thank you very much for the positive transaction and delivery of a working PCB to my CMU 200.
Now the RF generator works like new.
The repair of my CMU is closed, but no further modifications, I really like this machine and it is worth attention!
Thank you again to the Ice-Tea forum user
Greetings to all Kribok

[W3AXL]

Hi all!

Wondering if anyone is using their CMU200 with an external reference. I've got an HP Z3801 feeding into the unit at the REF IN port, and I keep getting "Reference frequency not locked" on the screen when I select external reference mode. I've verified that the output of the 3801 is a clean sinewave at about 3.5V pk-pk. Is the CMU picky about its input waveform, or is something else up?

Cheers!

[MarkW]

Hi All,

Maybe it is just me, but when I try to download the FreRes software from the R&S website I get a 'page not found'. Does anyone still have this laying around somewhere?

Thanks!

Mark

[ZL1CVD]

I saved them a while back. You can download then from here:
https://drive.google.com/open?id=154oZ86KouXtVO8aD0SCfACZSBnVj5Qa6

73s
Chris ZL1CVD

[MarkW]

Thanks!

[MarkW]

I tried out the FreRes application from R&S and I had two issues with it:

- It crashes when you try to normalize to a calibration run.
- It does not run on Linux.

So, I made a small python script that can do more or less the same and runs you through a calibration process. It works for 'thru' and 'reflection' measurements (when using a coupler or RF bridge). Hopefully it is useful for someone, feel free to modify or update it. The script assumes that you have linux-gpib running on your system.

The script is in the attachments, together with an example antenna measurement and filter measurement.

EDIT: updated the script to use 'read' instead of 'fetch' so it is synchronous with the initiated measurement.

Best regards,

Mark

[pedroavex]

Hi Manuel!

I have been looking for the R&S Remote Service Tool software to download, but cannot find it anywhere...
I've noticed you said something about having used it some time ago.
By lucky, do you still have its installation file?
Thanks from your neighbour from Portugal!

[lordium]

I have been looking for the R&S Remote Service Tool software to download, but cannot find it anywhere...
I've noticed you said something about having used it some time ago.
By lucky, do you still have its installation file?
Thanks from your neighbour from Portugal!

Here you go

[cdorsat]

Is your problem solved?  Is your problem solved? I have a CMR200 with FMR7. I don't know how to install the wiring of CMU-B41. Which master can help me?

[markus_jlrb]

Some infos concerning option B41  you will find

https://www.mikrocontroller.net/topic/432327#new

in the mc-forum (in German)

Markus

PS.: See https://www.mikrocontroller.net/attachment/338280/CMU-B41-Cabeling-Schema-missing-cabels.jpg
for cageling schama.

[Ice-Tea]

Wiring schematics is on the lid of the modules, no?

[cdorsat]

Thank you very much for your help, I have completed the installation of CMU-B41. It is not difficult.

[sab]

I corrupted my 64bit version of FreRes v5.30. Does anyone have a copy? I've scoured the web and been through the messages on eevblog and I've only been able to find v5.22.

I like 5.30 because you can do multiple measurements on the same screen and the values appear in different colors.

Thanks,

Sanjay

[_Wim_]

I corrupted my 64bit version of FreRes v5.30. Does anyone have a copy? I've scoured the web and been through the messages on eevblog and I've only been able to find v5.22.

I like 5.30 because you can do multiple measurements on the same screen and the values appear in different colors.

Thanks,

Sanjay

Just sent you a pm (was to big to upload here)

[sab]

Many Thanks _Wim_.

Sanjay

[mdmbc]

Any chance I could get a copy too? I've been searching for it for days..

[lordium]

https://www.mediafire.com/file/r20db9wsidjljkx/1MA009_FreRes32_5.3.0_a.exe/file
https://www.mediafire.com/file/1ryfcvox40o6lhq/1MA009_FreRes64_5.3.0.exe/file

or

链接：https://pan.baidu.com/s/1hky2fhkAUIkuu1J1mN74lQ
提取码：4pa4

if you have baidu. The baidu link contains a lot more. Including some pictures of the inside of my unit and the DD image from the HDD etc.

[Alfons]

I also bought a CM200 now. I only need the device for a few measurements on filters and to repair an old spectrum analyzer, otherwise I have really little to do with RF. I had looked around for alternatives, but good, functional single devices would have come much more expensive. In this case, I did not want any repair equipment, because I have no proper measuring equipment available for repairs of RF equipment. And the game with the whole China gadgets has annoyed me increasingly.

So I bought a CMU200 for 715 € (inc. Purchase), a lot of money (for a pure base unit, as I later discovered ). However, the seller has assured me, that the device is faultless. Only after the purchase, I noticed that it is a 1100.0008.30, so a basic device without any hardware options. The seller had agreed to a cancellation certainly, but then let it come. So it has only the generator, the analyzer and the power meter (saves electricity costs:)).

I then found that it works well and is completely sufficient for my purposes. I could not find any errors, all self-tests are "passed", the values ​​really good. The buttons work like the first day and the display is clear and bright. I'm impressed. It is easy to operate and even if the device is not a specialist in any of the disciplines, the performance for a relatively "new" device at the price is very good in my view. OK, the right ham radio hobbyists have more knowledge and will probably prefer single units. After the repairs, I'll probably sell it again. Maybe I will keep it too. Have fun with the device.

[Bicurico]

The other options, which you don't have, are completely useless, unless you want to specifically measure GSM/GPRS/Edge mobile communications.

You don't want to do these, because you should not transmit in the respective frequencies to begin with.

So be happy that you purchased a fully working CMU200. The price you paid is a great price, so no worries here, either.

The only option that might be somehow interesting (INHO) would be the Audio Measurement option. But again, you could probably do them in a more versatile way with a good PC audio card.

Check my blog for my "VMA Simple Spectrum Analyzer" software, which is available for the CMU200 & CRTU, too.

Regards,
Vitor

[Alfons]

Yes, I already know your software and will try it out in the next few days. OK, so the price for the device was OK. Actually, I wanted to update with the latest software, but the device don't accepts either the card reader or the CF card. Is formatted in FAT. Although I can see the files in the file manager, the version manager does not want to read the card.

Edit: Did not know that you have to extract the files. Now the update is running ...

[usagi]

as davey would put it, for the money the cmu200 is a real bobby dazzler 

even barebones it is impressive. but then it should be considering they originally ran anywhere from $20k-$100k depending on options.

[markus_jlrb]

@Alfons,

check out in addition the link in the german MC forum too in order
to find usefull infos concerning the CMU200.

https://www.mikrocontroller.net/forum/all?filter=CMU200*&x=0&y=0

Markus

[Alfons]

@Alfons,

check out in addition the link in the german MC forum too in order
to find usefull infos concerning the CMU200.

https://www.mikrocontroller.net/forum/all?filter=CMU200*&x=0&y=0

Markus

Of course, I have already read everything there about the device. And since I was waiting for the device, i already read everything worth about the device here on EEVblog and in the MC-forum So I was able to serve the device relatively quickly. I have just tried FreRes: really great, very useful.

What I've noticed is that you really need to have reasonable cables and connectors for the instrument to deliver accurate results. I'm not fortunate enough to have a few very high quality cables shipped from China some time ago. With my old cable, I could not perform the self-test error-free. Yes, I am new to RF.

[Alfons]

Had posted the question elsewhere, but I'll ask here:

In my MCU200 (1100.0008.30) the option cmu-U99 RF1 = RF2 limits the output power of RF1 to 2W. There is no second signal board installed, which usually sits where the heat sink is installed on the front end. The frontend in my Device is the "thick-one" with heat sink and fan. So there must be another reason why U99 is active and the RF1 / RF2 is limited to 2W. I do not think you can disable the cmu-U99 option. Or is that possible?
The 2Watt are also OK, you just have to be more careful with what you connect.

[markus_jlrb]

Alfons,

what you are looking for for high RF-Power output is showed on the top left position
of the picture linked below.

https://www.ebay.de/itm/Rohde-und-Schwarz-R-S-CMU200-Universal-Radio-Communication-Tester-Bastelpaket/174039616839?epid=1627651710&hash=item288591cd47:g:LXkAAOSw81Bdh3TT

You have to look for a corresponding spare PA module at Ebay.

Sorry to say.

Markus

[Alfons]

Alfons,

what you are looking for for high RF-Power output is showed on the top left position
of the picture linked below.

https://www.ebay.de/itm/Rohde-und-Schwarz-R-S-CMU200-Universal-Radio-Communication-Tester-Bastelpaket/174039616839?epid=1627651710&hash=item288591cd47:g:LXkAAOSw81Bdh3TT

You have to look for a corresponding spare PA module at Ebay.

Sorry to say.

Markus

I don't understand you: Why should I need a spare part? The front end works and it is the same as the one shown (at least externally identical). It is limited to 2W by the firmware, not by the hardware. At least I think so.  I think that another 50W frontend would not change anything.

And 33dBm should be enough for almost everything.

[Alfons]

Here is a graph from Freres, -30dBm between 100MHz to 2.7GHz. Is this ok? Measured with a 1m coax with adapter N-BNC between RF1 and RF3-Out. With better cables, you can certainly get a little more out and you have to rely on the fact, that the values ​​are correct. I can not compare, because I have no other measuring devices that can RF. As the level increases, the frequency response deteriorates by up to 1dBm, but is still within 2.5dBm. Between 100Mhz and 1Ghz the frequency response is straight.

[Sas]

Here is the graphic of my two cmu200. The cable is 0.5m RG316 N-N between RF2 IN and RF3 OUT.
The first CMU200A calibrated in 07.2017. CMU200A in the middle of 2018 had a deviation of not more than +/- 0.5 dBm. Currently it has worsened and has a deviation of ~ -1.5 dBm.
The second CMU200B was calibrated in 08.2015. I bought a damaged one. Missing dsp module, damaged disk, several cables, gsm modules were damaged. We managed to fix and run everything. The device does not pass the RF Loop Path 1 test correctly. The values are too low from - 2dBm to -5dBm. I can't calibrate it myself.

[Alfons]

Create a correction table yourself. There are instructions for this.

[Sas]

RF Loop Path 1 CMU200 with calibration 07.2017. A year ago it was +/- 0.5 dBm. Now it is +0.8 dBm / -0.9dBm. Correction table does not work in the RF Loop Path 1 test.

[Alfons]

@Sas: Is it possible to use one device to calibrate the other?

[Sas]

@Sas: Is it possible to use one device to calibrate the other?

Not by substituting correction tables for individual modules from another device. You can try to modify the correction tables of individual modules. The editing software should already be used in the device for factory calibration. I don't know any service mode or calibration method.
Correctly you would have to calibrate as R&S does. They probably use a good laboratory spectrum analyzer and generator. Another CMU200 is not a very good reference standard. I guess the calibration is limited to connecting, heating up and using ready-made software via GPIB or COM connector.

[Alfons]

I am an absolute beginner when it comes to SA. The device is great for learning. It is the first time that I am dealing with a (functional) SA and due to the variety of functions you do not need any other devices to try it out. Only slowly am I beginning to understand how an SA works at all, and now do I know what a reasonable spectrum has to look like and how it is also possible to generate a plausible FFT with a DSO. Because with some settings you can get quite good FFTs on a DSO. But extremely incomprehensible compared to the CMU200. Nevertheless, I am amazed to see that my old Infiniium offers a few options-settings, that you would otherwise rarely find on an old DSO for generating spectra (center frequency, span, power and phase and the possibility of setting the sampling-rate independently of the timebase-settings and the memory depth to influence the signal display ...). I only understood that, after I dealt intensively with the CMU. Because of this learning effect alone, it was worth buying the CMU200.

Nevertheless, there are still a lot of questions for me. I'm trying to understand what the I / Q-measuring on the device do. I/Q vs. Slots to measure the Phase-data in a signal-package, which is available in the basic menu and therefore not only to be used for measuring certain GSM etc.. signals?. This is the only option that my device has, which is also available in the basic menu.

Another question is: what does an OCXO do compared to the built-in TCXO in General-Purpose Measuring ? A Chinese dealer offers option B12 for around € 30. Does it make sense to retrofit that? I don't think so, because the accuracy of the TCXO is quite high. But what is your opinion?

[Ice-Tea]

The OXCO offers better timebase stability in the long run (will drift less over time) but it also drifts less with temperature variations in you lab etc. Unless you *know* you need it, I wouldn't bother. Accidently, another options is to use an external 10MHz reference. Which can be quite cheap as well.

[Alfons]

Thank you, Ice-Tea, I think I'll leave it that way and run it with the TCXO. At the moment I really don't know what I need an OCXO for. Highest to upgrade the device to get a better sales price. But I think I'll keep it anyway.

Here are a few more pictures: RF1-Out to RF4-IN. It generates and shows even very small signals quite well. But I don't really know if the measurement is OK. I switched off Avarage once, but that doesn't change much.

[Sas]

I don't have B17. I think it is a set of analog inputs and outputs of intermediate frequencies for external modulators and demodulators. There is also a set of IQ modulation inputs and outputs. I think that it is not very useful when working with analog modulations. Without the B17 module, only the 10.7MHz IF output of the receiver. This is the IF3 output after analog RX conversion and the analog input of the DSP module for digital analysis. Sound demodulation with analog modulation should not be a problem.
The TCXO oscillator is sufficient for a spectrum analyzer with RBW 10Hz. With the built-in OCXO, if you need to have a more accurate reading, you'll still use the external time base input for phase synchronization with other instruments.
In my first CMU200 there was already an OCXO generator at the time of purchase. I bought ocxo for the second CMU200 because of the pretty good tx generator with AM, FM, FM Stereo modulations. I also use the generator as a LO or RF signal mixer for the tracking generator. I use CMU200 as a working tool in an electronics workshop, it is not super accurate but universal, convenient interface and everything at hand. I do not regret buying OCXO. The original OCXO R&S module B12 for € 30 is a very good price. If you plan to sell it is probably an unnecessary investment.

[Alfons]

OK, I can try it out. But it has become a little more expensive? Well, 35 € is still OK. This one here: https://de.aliexpress.com/item/4000433902250.html?spm=a2g0s.9042311.0.0.672a4c4dukbieC

[Sas]

https://de.aliexpress.com/item/4000433902250.html?spm=a2g0s.9042311.0.0.672a4c4dukbieC

Wow 499 pieces! It's madness  . Is the choice which item will ship?
Pay attention to this auction for example https://www.ebay.com/itm/123957032489. One of these two B2 / B12 is damaged, the diode or resistor on the pcb is missing. This element is probably responsible for temperature measurement. It is easy to tear off during assembly and disassembly, as it is on the housing line when inserting and removing the ocxo. The fixing plate at the pins will also be useful.

[Alfons]

I often order things in China, mostly small things, but sometimes things that are a little more expensive. I've never had trouble. Defects are very rare and if you do, you can get your money back. I think buying is not a risk. Where did the dealer get 500 of them from? Perhaps R&S has already had production in China and are these remaining stocks? Fakes would not be worth it. I will see... Also: one bad rating and the dealer no longer sells more of this B12.

[Sas]

Perhaps these are unused or removed parts that were sent for recycling to China and went on sale again at a lower price. Write as you receive and it will work.

[Qw3rtzuiop]

These parts are probably from CMU200 that were used in china. A lot of CMU200 are used for cell phone prodution. Just take a look at CMU200 listings on Taobao.

[Alfons]

For 14 € I bought a cable on Ebay, which is equipped with Suhner plugs. Cable is F&G 213/U. Probably comes from military stocks, but in very good condition. With screw caps
I wanted to see, if anything actually happened in the frequency plot, connect with this cables. Yes, the frequency response is actually significantly better, now lies within -1.2dBm at -20dBm. That looks better.

[tech255]

The model number ending in .30 is a production line model normally banked in fours and is used to program and calibrate mobile phones as they move along the production line there is something embedded in the software that stops a lot of the options from working believe me i have tried.
After purchasing several scrap units i found one with a hard drive which was a .02 model this one is the best for modifications i now have every conceivable extra added and all of the latest software v5.22 i also have 50w input on channel 1 and +13dbm output from channel 3.
The audio board option B41 does not give you audio from the speaker its not available its for future development which is never going to happen, took me a while to work this out but it is possible to use the rf and audio together to get sinad and distortion readings but you need the Amps boards and software.
If anyone needs the latest software i can send it to you, i dont have a website you can obtain it from Rohde & Schwartz sent it to me after i contacted them about a fault.

[Alfons]

The module arrived today. For some time now, the shipping time from China has been significantly reduced. It usually takes about 2 weeks for parts that are a little more expensive. Only small parts take longer.

As described, the part is used, which is also clearly recognizable. But it looks undamaged, attempts of repair are also not visible. AR electronique, the manufacturer of the OCXO, is a French company, that specializes in the manufacture of quartz resonators, oscillators and piezoelectric filters. At least that sounds trustworthy.

If I have installed it, I will report. Next week I have a GPSDO here for a few days, so I can also check and adjust the frequency.

[Alfons]

Well, the installation was done in five minutes. The device recognized the module as B12 during booting, no further steps were necessary.

It seems to work. After a quarter of an hour warm-up, the signal shows an improvement. I still have to see, if I have comparison images, but the phase noise is obviously lower. Before that, I had a crater-shaped collar at the top of the bell. This has disappeared and the phase noise has decreased by about 7-10dBm (but only from my memory). I am really amazed to see that. In addition, the frequency display is now more accurate and the selective power meter shows the frequency in the last places much more quietly and precisely. So, it looks like the purchase was really worth it.

Edit: Since I was a little too quick, here is a Correction: the measurement accuracy has actually improved, but the phase noise is at best 3 dBm better, not 10 dBm. But I have to check it more closely. At least I can say that the module works well.

[heavenway]

Hi everybody!

new to this forum and really apriciate so much enthusiasm and competence, was wondering if some of you use the CMU200 in ham radio lab or for receivers/transmitters troubleshooting and align: will be glad for some advices in the case.

I am in the willing to buy one but... the only (and not small) limit it has is the spectrum scope that starts at 10mhz, and its a big limit for me.

cheers

[Ringmodulator]

Hi,

there is a solution for this:

Look on Ebay for CMU200 10MHz Spectrum Analyzer Expansion for Radio Communications Test.

It is just a simple mixer. Works for me.

Chris

[heavenway]

thank u Chris, seems to be upconvert dc-10mhz signals or am i wrong? still looking for a good unit to my purposes .02 of course 

[Ringmodulator]

Yes, it uses the CMU200 RF out as LO at 2GHz.
0-10MHz will then be upconverted to 2.0-2.01 GHz and you can display the spectrum there.

There are similar mixers available on ebay with a shielded housing, which will also do the job.
Then you need cables and adaptors seperatly.

Regards
Chris

[heavenway]

need te CMU200 first 

[balage]

I think the Ebay mixers have the HMC213 IC from Hittie/Analog Devices. Can anybody confirm this?

I am building my own, with a self-designed PCB. I think I will sell out the remaining PCBs.

[Ringmodulator]

Hi,

mine is on a BG7TBL board and uses a HMC213.
There is nothing else beside this one and the SMAs on the board.

Chis

[Ringmodulator]

Hi balage,

you can get them ready made with HMC213 for under 20$ delivered.
https://www.ebay.com/itm/HMC213-RF-Passive-Double-Balanced-Mixer-Diode-Frequency-Conversion-Module/264330247742

Chris

[balage]

Hi Ringmodulator,

Oh, if I would have found the enclosed earlier, I would bought one. Especially HMC213 costs 15 bucks. 

Anyway, it was fun to design my own board...

[Sas]

@tech255 I have two .02 CMU, one older with PS2 and newer with USB. Both units are removed from the production line, have a generator +13dBm RF3 OUT and only 2W RF1 input. They also have a second generator, B41 and all GSM modules.

@Alfons B12 looks good. I don't know this Pulsar 510 oscillator. I think it is low phase noise ocxo. I calibrate my ocxo once a year, the error is less than 0.1Hz @10MHz.

I use the Anzac (macom) MDC-162 mixer. I amplify the IF from RX / TX module with a 40dB @2-4GHz old cascade amplifier mounted inside and powered from the CMU. At the amplifier output I have about +10dBm, good level to control the LO input of the mixer. Mixer conversion losses around 8dB, RF3 OUT generator output +13dBm level is enough to get 0dBm. I miss the AGC, because of course CMU has no normalization function for tracking generator.

[Alfons]

Have now tried the B12-OCXO to compare with the GPSDO as a reference. After the GPSDO had been in operation for three days and nights continuously, I tried to take the phase curve on the oscilloscope to cover. Even without adjustment, the B12-OCXO signal was quite close to the GSPDO and only migrated very slowly.

The best thing I can set is that the signals move against each other at around 20ns per hour. If I turn the spindle trimmer just a mini-mini-tick, the direction changes, I can't find a sync. So there is nothing more. I might be able to get slightly better results by changing the value of the spindle trimmer, but I don't think that will work for long time. I guess everything will be slightly shifted again after restarting the GPSDO.
If I connect the GPSDO to the input of the CMU200, the integrated counter shows me the 10MHz down to 9 digits, the tenth digit oscillates between 1 and 0, the 11 digit fidgets. That is stable.

[Alfons]

After the signal has moved to the right for approx. 24 hours, it now runs to the left. That commutes back and forth about every 24 hours. The phase shift can hardly be seen with the naked eye. Is this commute normally?

[Sas]

After the signal has moved to the right for approx. 24 hours, it now runs to the left. That commutes back and forth about every 24 hours. The phase shift can hardly be seen with the naked eye. Is this commute normally?

A question without a clear answer. It is not possible to set the frequency perfectly, the frequency deviation is always there.
We can only create wrong theories. Assuming that you set the ocxo generator perfectly, the GPSDO itself will change the phase shift once a day, along with the synchronization of the satellites with the standard time atomic clocks. Phase shift and drift to the left or right would be due to the low DAC resolution in GPSDO, one bit lower and one bit higher. This setting of ocxo alone is impossible, ocxo has too low accuracy. My cesium clock pulls phase shift over 36h and 2.8E-13 stability takes 5 days GPS tracking. I don't know if by chance the GPS update is currently not every 12 hours.
There are different ocxo generators, used after prolonged shutdown, shocks, shocks require several cycles to stabilize again. Frequency may depend on many factors. From temperature, reference voltage standard, supply voltage, output load, interference, altitude above ground, earth's magnetic field, etc. However, it most likely depends on ocxo consumption. Turning ocxo off and on again is a different frequency and never the same. Set with 0.01Hz accuracy at 10MHz. After many turns on and off, it will out of tune anyway 

[Alfons]

@Sas, thanks for the answer.
Some reports from users say, that the signals would run synchronously. But I can't imagine that either, because there will always be a slight drift. I'm still trying to figure out how big the drift is, how I calculate it. I have to familiarize myself with it, just out of interest. I think the accuracy that I have now is enough for the CMU200.

[Ice-Tea]

Was a bit curious, so took a few pics of a "naked" TX/RX board. Figured I'd share. Not scaled. Enjoy!

[Robert763]

- Is it possible to make a print screen save it a usb stick

In my CRTU I bought a PCMCIA to SD adapter to make screen dumps, but all attempts with different card sizes have been unsuccessful, although someone told me it worked in his unit.

This is an old post I know, but I just found it and can give you an answer. The CMU200 CRTU-RU basically runs DOS 6.22 and the PCMCIA interface uses the ATA (IDE) hard disc emulation mode. This mode uses a parallel interface and is not supported by SD cards as they only have a serial interface. Like wise the simple PCMCIA to SD adaptors do not support it either. Compact Flash (CF) cards do support ATA mode so a PCMCIA to CF adaptor will work.

[dcarr]

I have a working CMU200 -> MMC (SD) card setup.  See the pictures below for the PCMCIA adapter and the MMC card I use.  I suspect that the it's important to use a SD (or MMC) card below a certain size...

[ps]

  I suspect that the it's important to use a SD (or MMC) card below a certain size...

At least you can exclude everything above 2 GB because this is the maximum possible size for a SD/MMC card. Anything bigger is SDHC or SDXC.

[lucaspnw]

Hi thread. I just got a CMU200, and after some keyboard / battery repair it works. It's quite old and uses BASE 3.52. It does have B12, B21 (Universal Signaling Unit), B41 (audio), B52 (speech coder), B53 (Bluetooth), and B83.
It does have 256MB RAM and the AMD K6.

It seems to work OK. I'd like to upgrade this unit to do AMPS and Bluetooth and other software features.

Does anyone have the 5.21 software for this unit? I've tried creating a Versions.new and copying BASEV5.21.exe and other files to the PCMCIA, but the versionmanager program does not list the "Install software" option. I've also tried to copy BASEV5.21.exe to C:\INTERNAL\INSTALL, but this also does not cause the install option to appear.
I do know the PCMCIA is working because versionmanager does successfully copy the log files to it when asked.

Thanks in advance!

[_Wim_]

Hi thread. I just got a CMU200, and after some keyboard / battery repair it works. It's quite old and uses BASE 3.52. It does have B12, B21 (Universal Signaling Unit), B41 (audio), B52 (speech coder), B53 (Bluetooth), and B83.
It does have 256MB RAM and the AMD K6.

It seems to work OK. I'd like to upgrade this unit to do AMPS and Bluetooth and other software features.

Does anyone have the 5.21 software for this unit? I've tried creating a Versions.new and copying BASEV5.21.exe and other files to the PCMCIA, but the versionmanager program does not list the "Install software" option. I've also tried to copy BASEV5.21.exe to C:\INTERNAL\INSTALL, but this also does not cause the install option to appear.
I do know the PCMCIA is working because versionmanager does successfully copy the log files to it when asked.

Thanks in advance!

Here you can find what you need:
http://gotroot.ca/cmu200/

Exta info nicely grouped together:
http://vk4zxi.blogspot.com/2018/07/rohde-schwarz-cmu200.html


Edit: I upgraded mine to V5.21, but using an Agilent 82357b GPIB adaptor and the "remoteservicetool" software from R&S

[_Wim_]

This is the remote service tool software I used

[Qw3rtzuiop]

@lucaspnw

You need to execute the BASEV5.21.exe on your computer. It is a self extracting zip file.
You can also open the .exe with 7-Zip to get the files.
Than copy the new BASEV5.21 folder on your CF-card.

[om4ik]

Hallo

Can anybody send me bios for CMU 200 FMR6 PC board please (pentium 933MHz) ?
Very Thanx

[lucaspnw]

Thanks for the replies!
Everything worked great, upgrade no problem.

Decompress the EXE files to separate directories on the PCMCIA card named after the files/versions. Ex:

├── BLTHV5.20
│   ├── ARC000.MD5
│   ├── ARC001.MD5
│   ├── ARCHIV.000
│   ├── ARCHIV.001
│   ├── CONFIG.INI
│   ├── archiv.exe
│   ├── prepupgd.bat
│   ├── readme.txt
│   ├── reconf.bat
│   ├── release.txt
│   ├── untgz.exe
│   └── untgz.md5
├── CD2KV5.20
│   ├── ARC000.MD5
│   ├── ARC001.MD5
│   ├── ARC002.MD5
│   ├── ARC003.MD5
│   ├── ARC004.MD5
│   ├── ARC005.MD5
│   ├── ARC006.MD5
│   ├── ARC007.MD5
│   ├── ARC008.MD5
│   ├── ARC009.MD5
│   ├── ARCHIV.000
│   ├── ARCHIV.001
│   ├── ARCHIV.002
│   ├── ARCHIV.003
│   ├── ARCHIV.004
│   ├── ARCHIV.005
│   ├── ARCHIV.006
│   ├── ARCHIV.007
│   ├── ARCHIV.008
│   ├── ARCHIV.009
│   ├── CONFIG.INI
│   ├── Prepupgd.bat
│   ├── UNTGZ.md5
│   ├── archiv.exe
│   ├── readme.txt
│   ├── reconf.bat
│   ├── release.txt
│   └── untgz.exe

[hi3cmz]

Hi, sorry for hijak the thread, but I am pretty sure that here is the place some if not all of my question might be answered.

1- Does cmu200 or CRTU-RU works under 100 khz? say 85 Khz?
2- It is possible to, modify as less as possible, write/append new K-like options that one need into CMU200, CRTU-RU/PU?
3- If preview question is yes, then what will be better, CMU200 or CRTU-RU?


Thanks!

[Octane]

Hi,

I’m pretty sure, the following answers are correct:

1) No. as far as I remember the generator starts at 100kHz and the spectrum analyzer at 10MHz. Or the other way round.

2) I doubt it. Everything is closed source.

3) N/A

4) I don’t understand the question...

5) The AMU200 is a totally different thing. It is a baseband signal generator and fading simulator.


I hope that answers your questions at least partly.

BR,
Michael

[Octane]

Hi,

Does anyone know the differences between a CMU200 and a CMU300 by heart? Looking through the specs and manuals they seem identical.

Thanks,
Michael

[Robert763]

I have a working CMU200 -> MMC (SD) card setup.  See the pictures below for the PCMCIA adapter and the MMC card I use.  I suspect that the it's important to use a SD (or MMC) card below a certain size...

I suspect that your setup works because that is not a simple SD card adaptor. It is an older multiformat SD, Sony Stick, Xd etc adaptor. This meains it has a conroller and probably presents the PC interface as ATA parallel.

Robert G8RPI.

[Robert763]

Hi,

Does anyone know the differences between a CMU200 and a CMU300 by heart? Looking through the specs and manuals they seem identical.

Thanks,
Michael

The CMU-300 was configured / marketed for base station testing. The only significant difference is that only the 300 supports the B71 ABIS interface option. This provides a E1/T1 line interface that is used for wired communication with cellular base stations. No use what so ever to the average RF user. So unless you are testing base stations the 300 can be considered identical to the 200 with same options fitted.

Robert G8RPI.

[szszjdb]

Anyone could help ?

The RF generator of my cmu200 dead. Running the RXTX1 selftest, all passed. But fail all in the internal RF loop selftest with no signal detected at all. Checked with another SA, the SG output a small signal nearly -60dbm than it is set.  The RX path seems ok checked with anther SG.
Checked the  service manual online  , found no schematics of the RXTX board. Does anyone got the full version of service manual?
As the 3 tx LO were pass the selftest, the issue should be on some RF switch?

Best Regards,

[szszjdb]

Hello everybody,
Does anyone know the component in the RXTX PCB, as attached picture? The yellow one with 4 signal port. I am tracing the signal flow and confused with this part.

Best Regards,

[ZL1CVD]

looks like a SMD filter

[ZL1CVD]

This is the block diagram for RX/TX if you need it..

[szszjdb]

Hi,ZL1CVD,
Many thanks for your kindly help!
The part have 4 signal port in the middle and the common filter just have two. That is what I am confusing. Or transformer or coupler?
It seems R/S did not provide the full detail schematics of RXTX pcb. Am I right?

Best Regards,

[Ice-Tea]

Aside from the block diagram, I never found schematics.

[ZL1CVD]

I haven't see schematics either.
There is 3 of those in the RXTX module. They could be a diplexer which would have at least 3 ports. Some filter used in cellular look like they have multiple ports but really only have 2 with lots of grounding points. I think its they way they etch the ceramic.

[szszjdb]

Hi,ZL1CVD and Ice-Tea,
Thank you!

The part already have 4 GND port at the corner and 4 signal port in the middle.
From the layout, it seems 2 port pass the 842mhz signal and the other pass the 1.2-2.2g signal. It is interesting to learn about the function of it.

Best Regards,

[a_q]

Hi,

Does anyone know the differences between a CMU200 and a CMU300 by heart? Looking through the specs and manuals they seem identical.

Thanks,
Michael

There are indeed some significant differences. As the CMU-300 is for testing the GSM BTS, it has one RF input that's capable of accepting a full 50W RF power. Mind you, when you stick in above 30W it does start to get a bit smelly!

It has a nice spectrum analyser (up to 2GHz as I recall) and also a signal generator with some modulation options. You can use these combined to test RF components, amplifiers, cables etc.

I would challenge anyone to come up with a spectrum analyser with a 50W input - calibrated.

[Qw3rtzuiop]

There are indeed some significant differences. As the CMU-300 is for testing the GSM BTS, it has one RF input that's capable of accepting a full 50W RF power. Mind you, when you stick in above 30W it does start to get a bit smelly!

Without the additional RF Generator (i think its option B96) the normal CMU200 can also take 50W.

[colorado.rob]

I just picked up a R&S CMU200 and it has B96, but I would rather have 50W input.  Can I remove the B96 option and restore the 50W input power handling?

[Ice-Tea]

As far as I know, the front end is different (including a fan to cool the input) so perhaps you can swap out the front end but its not like you can uninstall an option or something

[colorado.rob]

As far as I know, the front end is different (including a fan to cool the input) so perhaps you can swap out the front end but its not like you can uninstall an option or something

Thanks for the response.  Not what I wanted to hear, but an answer I can live with.

Next question: can I use a PCMCIA SD Card reader to load new software?  I see most people using PCMCIA CF readers.  Just wanted to know if I would run into trouble using a SD reader instead.

[colorado.rob]

Does the CMU200 have anything like the Agilent/Keysight 89600 VSA software available for it?

[Qw3rtzuiop]

I dont know what features the Keysight Software has but you can use R&S Commander to take copies, access the file system or record traces.

[niconiconi]

I have a working CMU200 -> MMC (SD) card setup.  See the pictures below for the PCMCIA adapter and the MMC card I use.  I suspect that the it's important to use a SD (or MMC) card below a certain size...

I suspect that your setup works because that is not a simple SD card adaptor. It is an older multiformat SD, Sony Stick, Xd etc adaptor. This meains it has a conroller and probably presents the PC interface as ATA parallel.

Robert G8RPI.

It must have a controller and possibly firmware inside, emulating as a True-IDE mode CF Card.

As far as I know, the front end is different (including a fan to cool the input) so perhaps you can swap out the front end but its not like you can uninstall an option or something

Thanks for the response.  Not what I wanted to hear, but an answer I can live with.

Next question: can I use a PCMCIA SD Card reader to load new software?  I see most people using PCMCIA CF readers.  Just wanted to know if I would run into trouble using a SD reader instead.

Yes, you probably can. I'm using a PCMCIA SD Card reader for making screenshots on my CMU200 without any problem. Disclaimer: I had only attempted making screenshots and using the card in MS-DOS, I didn't try loading new software, so there's no guarantee, but I can't see why it won't work.

The card reader is a no-name brand with a fake "Mercedes-Benz" logo on it, apparently sold as adapters to play music on old cars, nevertheless works fine for my purpose. But you need to make sure the SD card is compatible with the reader itself, and the card formatted properly to be compatible with MS-DOS.

* First, avoid using those super high density 64 GB SDXC cards, a 16 GB one or smaller card should work. Even better, use an old 1 GB card in your desk drawer specifically for the use in CMU200.

* The card must have a MBR partition table with 1 primary partition. Do not create a raw filesystem without partition table. Do not create more than one partition. Do not create extended partitions. The size of the primary partition should not be greater than 2 GiB, even if the card is larger.

* The filesystem on the first primary partition must be FAT16. Do not create a FAT32 filesystem, otherwise MS-DOS will still try interpreting it as FAT16, and corrupt the entire filesystem.

* Use a standard USB card reader on your PC to format the card. Do not plug the CF reader to the CMU200 or your vintage laptop to do it. It seems the firmware on my card reader is rather limited, doing any low-level operation can confuse the firmware and corrupt the partition table. I tried formatting the card in the reader itself on a vintage laptop, after created a partition and putting it in a standard SD card reader, I see a partition table with a 1000 GB partition.

After you've prepared the card, you should be able to make screenshots. On my model, it works in the second slot. Press Alt + F4 to enter MS-DOS, it should be recognized by MS-DOS as Drive D, and "dir" should reports the correct volume size (otherwise it indicates something must be wrong, e.g. DOS attempts to read FAT32 as FAT16). You can also run scandisk on the card, and it should always pass the check.

Incorrectly formatting SD card can freeze and crash the CMU200. But once the card has been formatted, it's just plug and play.

[_Wim_]

Does the CMU200 have anything like the Agilent/Keysight 89600 VSA software available for it?

There is also "FreRes" to take frequency sweeps, "CMUGo" to run measurement sequences and "VMA Spectrum Analyser for CRTU" which is maybe the closest to the keysight VSA  software (but not free).

[switchabl]

The VMA software doesn't seem to support any modulation analysis though.

There is an option to record raw I/Q samples and send them over GPIB (look for IQRecorder in the manual). It should be possibly to write these into a CSV file and import them into the Keysight VSA software. Unfortunately, the maximum capture length is 32k/64k samples (depending on options) which may be quite limiting.

[arno]

Hello everybody,

I bought a used CMU200 two weeks ago. Everything worked fine until yesterday. Unplugged it from mains in the morning, replugged in the afternoon, fans came up for a couple of seconds, the power LEDs were still green, not orange. I am also able to go into standby by pressing the power button for a couple of seconds, but after re-powering the fans come up for a few seconds, then turn off. I already took of the case and all LEDs on the bottom of the mainboard light up after turning the unit on, but then go off. To my understanding the issue must be somewhere else but the PSU.

Thanks in advance,
Arno

[dencyaupin]

Hello everybody! Help with troubleshooting and identify mixer board details.

[_Wim_]

Hello everybody,

I bought a used CMU200 two weeks ago. Everything worked fine until yesterday. Unplugged it from mains in the morning, replugged in the afternoon, fans came up for a couple of seconds, the power LEDs were still green, not orange. I am also able to go into standby by pressing the power button for a couple of seconds, but after re-powering the fans come up for a few seconds, then turn off. I already took of the case and all LEDs on the bottom of the mainboard light up after turning the unit on, but then go off. To my understanding the issue must be somewhere else but the PSU.

Thanks in advance,
Arno

Maybe also a keyboard related issue?

https://www.eevblog.com/forum/repair/cmu200-boot-failure-power-suplly-erratic/msg1193017/#msg1193017

[arno]

Dear Wim,
thank you for the hint. As far as I could investigate, the keyboard is not the cause.

Arno

[_Wim_]

According to your symptoms it does indeed seem a short circuit is present somewhere. So first thing to do it find the faulty module.

[_Wim_]

According to your symptoms it does indeed seem a short circuit is present somewhere. So first thing to do it find the faulty module.

Screenshot from pag 112 of this service manual: http://gotroot.ca/cmu200/RS_CMU200_CMU300_other.pdf

[arno]

Wim, thank you very much for your help, I really appreciate that. Today I had no free time to keep on the investigation but will come back asap.

Arno

[arno]

Hello everybody,

today I measured all the voltages at the test points next to the LEDs. In the moment the unit powers off, there is a huge peak on the rails of 3.3V and 6V (my multimeter [Keysight U1272A] peaked 28V). Have not yet measured with the scope. Took the whole PSU apart, but there are no visible faults at all.

Arno

[_Wim_]

Hello everybody,

today I measured all the voltages at the test points next to the LEDs. In the moment the unit powers off, there is a huge peak on the rails of 3.3V and 6V (my multimeter [Keysight U1272A] peaked 28V). Have not yet measured with the scope. Took the whole PSU apart, but there are no visible faults at all.

Arno

I would try to remove all plugin modules and see it the motherboard boots. If the rails are ok before it turns off, my guess would be this is only a turn off glitch with no actual power in it. When it boots with no plugin, reinstall one card at a time and check if it still boots with the added card.

Be sure to take pictures before removing cards, so you exactly know were everything goes when reassembling.

[Ice-Tea]

Check all flatcables on the motherboard. A half unplugged cable has ruined my day once or twice in these machines.

What I've also seen to result in startup issues: the front (computer) module has a fairly weak fan that goes bad and seizes after time. The elcos on the board dry out, behaviour becomes eratic. Often visible cap damage. Worth checking out.

[richnormand]

The PSU can run OK without a load when provided with a good start signal.
I do not remember a spike at start-up.

There was a long thread on fixing the CMU200 PSU with lots of details on it. In particular how to start it when out of the unit for testing.
It can run OK without a load.

EDIT
Here it is:
https://www.eevblog.com/forum/repair/rohde-schwartz-universal-radio-communication-tester-cmu200-psu-issues/

I'll find it and edit this post when I do.
1)
The start up spike is worrying. Can you scope it to see if it is real?

2)
Check all the PSU filter electrolytics.

3)
Remove all the plug-ins (over load can shut down the PSU) and also see if the front processor board boots OK and does not initiate a shutdown.

4)
Mentioned above, the small fan on mine was seized. Easy to dismantle and oil. Been OK for several years now.
Did the same for the main fan.

Good luck with it.

 

[arno]

Dear all,

the CMU is back up running. I simply cleaned the PSU using flux cleaner (there was a little bit of dust on the PCBs). Also, I could already swap the HDD for a SSD. Self tests are passing.
Thanks again for your help!

Arno

[_Wim_]

Dear all,

the CMU is back up running. I simply cleaned the PSU using flux cleaner (there was a little bit of dust on the PCBs). Also, I could already swap the HDD for a SSD. Self tests are passing.
Thanks again for your help!

Arno

Good news! Enjoy your unit!

[arno]

Hi, it's me again.
Re-Assembled the unit today and there is something really wrong with it on the RF side. When I send in 0 dBm it reads about -30 dBm and the generator is about 50 dB lower than it should be. Is it possible it lost all it's calibration during the repair? Is the reference somehow broken?
When I run the internal loopback tests (1->4 / 2->3) / Internal RF Loop, it does not read any power at all.

Thanks in advance!
Arno

[capt bullshot]

Loopback tests  (1->4 / 2->3) require an external cable connection between the mentioned ports (just in case you didn't notice that).

 If it's only these tests that fail, I'd check the RX/TX module without the RF front end connected (remove the two hardlines from RX/TX to RF frontend) and measure directly at the RX/TX module SMA connectors. There's just a (quite convoluted) bunch of RF switches and gain blocks within the RF front end, all the basic functions of the CMU will operate with the front end disconnected, levels will be off by a few dBs.

Port 3 and Port 4 have MMIC amplifiers more or less directly coupled to the connectors, these might be shot by externally applied DC or whatever, causing the external loop tests to fail. Port 1 and Port 2 will continue to work anyway, if this is the issue.

[richnormand]

Loopback Rx/Tx tests:

I would make sure loop cables is hooked up in front (good quality cables needed)
I would check the various flat cables to the unit.
I would check the SMA lines under the mainboard are connected connecting to the Tx/Tr module and that it is well seated in the main connector.

Lots of info in this thread:
https://www.eevblog.com/forum/repair/rohde-and-schwartz-cmu200-rxtx-module-issues/

[_Wim_]

Loopback tests  (1->4 / 2->3) require an external cable connection between the mentioned ports (just in case you didn't notice that).

Indeed, but as there is quite a bit of cross-talk between the channels, this can be confusion because your actually seeing a signal, but it is just to low...

[arno]

Dear all,
thanks for so many replies. I unplugged the front RF module from the RXTX-board and connected both SMA connectors. Then, in RF1 internal loopback test, I saw around -30 dBm, but ONLY in Bd (I assume band) 5, between 2.2 and 2.7 GHz. The rest is still dead. Also, I do not see any RF power from the TX out. 

Edit: opened up the RXTX-unit. There are no visible damages, like broken caps or something, just some dust.

Thanks
Arno

[arno]

Dear all,

sorry for the long break, I was quite busy and could not work on my CMU. Luckily I found a replacement RXTX-Board and the unit is fully working, again!   

Thank you all for your help!

Arno

[richnormand]

Hi arno,
just sent you a pm.
Cheers

[Decee1]

Hello.
Anyone can help with my issue? I am getting nowhere with it..
https://www.eevblog.com/forum/rf-microwave/rs-cmu200-gpibcom-communication-problems/

[webxtor]

Hello.
Here some company sells the equipment used for mobile phones repair and I am expanding my own amateur workshop.
So now this device is on the auction and I am trying to find out the possible use of it.
As far as I understood it does not support 4g/LTE or newer networks and may thus be used only as a toy and nothing serious about the modern phones?
What is the application for it you have found nowadays?

Thanks

[capt bullshot]

The CMU200 is still useful as a spectrum analyzer (10MHz to 2.7GHz) and signal generator (up to 2.7GHz) for general use.

[CJay]

Hello.
Here some company sells the equipment used for mobile phones repair and I am expanding my own amateur workshop.
So now this device is on the auction and I am trying to find out the possible use of it.
As far as I understood it does not support 4g/LTE or newer networks and may thus be used only as a toy and nothing serious about the modern phones?
What is the application for it you have found nowadays?

Thanks

Depends what options are available on the unit you buy but the one I have is pretty useful for me.

It works as a spectrum analyser, it has dual RF signal generators, I can use it to analyse filters, antennas etc..

It also has the audio module s it's as a simple audio analyser and audio signal generator, I can also measure SINAD, Audio power and RF power with it.

 

[486dx4]

Hi - just reading the posts.  Where can one get the latest version of FreRes these days.  I did find version 4.3.1 but I do see screenshots of a version 5.x.x  The links given in the older posts do not seem to be valid anymore and searching for the application note 1ma09 on the Rohde website comes up with nothing (granted this software is old now I'd say).  If anyone happnes to have info on where to download that would be great. 

[_Wim_]

Hi - just reading the posts.  Where can one get the latest version of FreRes these days.  I did find version 4.3.1 but I do see screenshots of a version 5.x.x  The links given in the older posts do not seem to be valid anymore and searching for the application note 1ma09 on the Rohde website comes up with nothing (granted this software is old now I'd say).  If anyone happnes to have info on where to download that would be great.

This is the latest version I have (will be 4 parts). File to be renamed to "1MA009_FreRes64_522.z01" as only zip files are allowed.

[_Wim_]

This is the latest version I have (will be 4 parts).

Rename to "1MA009_FreRes64_522.z02"

[_Wim_]

This is the latest version I have (will be 4 parts).

Rename to "1MA009_FreRes64_522.z03"

[_Wim_]

This is the latest version I have (will be 4 parts).

Final part (no renaming required). Enjoy!

[Robert763]

I'm having trouble with FreRes and a CMU200 (Actually a CRTU-RU running CMU200 Base software). The problem has been reported here before but no solution (other than a Python script). The issue is normalisation. you can do a sweep and click the normailse button and all seems OK. But when you click the play/sweep button next the program crashes. Happens with both FreRes64 5.55 and 5.30 on a R&S CMW-CU (Windows Embedded).
Anyone seen this or have a fix?

[Robert763]

So I've been having a play and found a work-around for the normalise crashing FreRes. It might actually be how it's supposed to work, but not according to the help file.

You make the reference sweep with the Sweep / Play button.
Then click the normalise button. You should get a flat line.
Change the test component setup as required then click the REPEAT button.
You can click repeat multiple times.

[_Wim_]

So I've been having a play and found a work-around for the normalise crashing FreRes. It might actually be how it's supposed to work, but not according to the help file.

You make the reference sweep with the Sweep / Play button.
Then click the normalise button. You should get a flat line.
Change the test component setup as required then click the REPEAT button.
You can click repeat multiple times.

Thanks for posting this! I remember I also tried this function, but gave up.

[RBBVNL9]

For all those interested in getting a CMU200 – or perhaps already have one – I recently posted a series of videos discussing the use of the CMU as a general-purpose measurement device:

REL #18 Using a CMU200 in the 2020s
REL #19 CMU200 Checking its condition
REL #20 CMU200 Update Firmware ?!?
REL #21 CMU200 RF I/O power levels
REL #22 CMU200 as an RF Power Meter

In every episode, I try to add less-known facts, information, and tips. For instance, #21 and #22 show the schematics of the diode-based power meter implemented in the CMU.



In the future, I plan to add the following episodes:
-   CMU200 as a spectrum analyzer
-   CMU200 as an RF signal generator
-   CMU200 as an audio analyzer

Hope you enjoy the videos! And if you have specific tips or ideas on what the videos should include, let me know…

[usagi]

CMU200 as a spectrum analyzer would be the best video to do 

don't forget the use of freeres as a tracking generator.

[richnormand]

All excellent suggestions RBBVNL9.

They cover all the useful stuff for someone that picked up a CMU200 for use as an instrument instead of a cell phone testing device.
Of note are the mixers also available on ebay to extend the low frequency range of the SA that you could include. They are inexpensive and easy to use.

Also. how about a video for installation of the B17 I/Q IF interface option module.
It is a popular add-on for the CMU200 that do not have it and they are available on ebay.
You could also talk of what are incompatibilities with some existing modules and such.
A second video about its usage and performance would complete the set.

Another on is the high stability reference oscillator B12 option that is also widely available.

Appreciate your videos, please continue the good work.
Cheers....

[pdenisowski]

Appreciate your videos, please continue the good work.

Yes, those are really great videos - thanks @rbbvnl9 for making them!

Glad to see the CMU is still being used:  we made (literally) tens of thousands of them.  There was even one on display at the Deutsches Museuem in Munich at one point

[RBBVNL9]

Dear all, thanks for the compliments. Positive feedback is helping me to keep going on this ;-)

Concerning hardware…

CMU200 as a spectrum analyzer would be the best video to do 

Certainly. It's in my planning!

Also. how about a video for installation of the B17 I/Q IF interface option module.

Also planned ;-) Have already bought this module a couple of months ago, which I will use for this!

But it may take a moment; currently I am working for a while in Japan, and travelling around that country. 

Concerning software…

Now, here is where it gets a bit more complicated. My current thinking is to test the following:

• Remote Service Tool V1.7.1 (by R&S)
• FreRes (by R&S)
• CMUgo (by R&S)
• VMA Spectrum Analyzer (by Vitor)

The issue is that I do not get these all to work. I purchased a Keysight/Agilent 82357B USB/GPIB Interface and installed the Keysight IO Libraries Suite 15 on a contemporary PC running Windows 10. I think this Keysight solution is a rather common one, and also the documentation of R&S on this usually refers to the Keysight IO Libraries as one of the supported options, if not the preferred connection option. While the Keysight IO Libraries Suite 15 perfectly sees all my CMU’s and other GPIB devices, I struggle with the above software to get it connected in the first place (FreRes) or working properly (the others).

When I get back from Japan and have time to test this a bit more, I will post a more specific post in the already existing FreRes thread. But what is not helping either is that (1) that R&S only seems to post older versions of this software on the website (v3.22 is here), but I know the newest one is at least 5.3.0; (2) the four R&S FreRes manuals I managed to find are different in terms of compatibility requirements listed, but these manuals do no state to which software version they correspond (and adding to the difficulty is that that two rather difference manuals have the same reference (1MA09_4E) ?!?

Perhaps the issues relate to using a much later Windows version than that was available when this software was developed, so I am considering to also set up a much older PC (Windows XP?) as a kind of sandbox and installing the Keysight IO Libraries in an older version (e.g., from the CD that shipped with the GPIB interface) to see whether that gives more luck…

Best, Rudi

[Bicurico]

Hello Rudi,

Drop me an email and I will help you with the connection.

Also, on my blog you will find an entry on how to configure everything. Note that you need to run FW starting with 4.xx to be able to connect and you need to configure primary and secondary address.

Regards,
Vitor

[RBBVNL9]

Dear Vitor,

I did manage to get VMA Spectrum Analyzer running - I should have been more clear on this. Really like it, especially the waterfall plot, allowing to see certain patterns for time-dependent signals. Only wish the waterfall could be shown larger ;-)

Best, Rudi

[RBBVNL9]

The CMU200 can output its screen to an external VGA monitor – fairly standard 640 x 480 pixels mode – and senses at boot whether such a monitor is connected; otherwise, this output remains disabled.

I have several CMUs and want to use a ‘mechanical’ VGA switch to select which CMUs screen to show on a monitor (and at the same time send it to a video-grabbing device). Because of the sensing part, my current procedure is rather cumbersome: I need to select each CMU one by one on the VGA switch, have it boot up, then go to the next one, etc. I would rather be able to turn all CMUs and make them all believe there is a monitor connected.

Doing some quick search, I understand that, over time, different methods were used to sense a monitor via VGA:
-   A resistance of 75 ohms between each video output line (R, G, B) to ground.
-   Connect any (combination) of the Monitor ID Bits (pin 11, 12, and 15 for bit0, bit1 and bit2, respectively).
-   An I²C signal (SDA on pin 12, SLC on pin 15), used by the VGA Video BIOS to access a 128 byte or 256 byte serial EEPROM memory in the monitor to determine its specifications.

 Before I go into measuring and digging this out, is there anyone that knows how the CMU senses the presence of a monitor? If yes, that would be quite helpful…

I have a bit of the same question for my AMU200A. It has a more advanced video card than the CMU, and runs Windows XP Embedded, and may or may not sense the monitor the same way as the CMU does…

Thanks! Rudi

[William]

I have the same (problem 2 watt on a what shoud be 50 Watt on a 1100-0008-30

Did you solve it and would you like to share a solution. or is a .02 simple the better solution, i still can switch.
Regards William

[ps]

50 W input capability requires a big 50 termination resistor inside the RF frontend, plus some nice heatsink fins at the bottom of this module. There is an optional second RF generator, that sits exactly at this position. Option B95 or 96 or something like this. So whenever this second generator is present, you do not have the heatsink and therefore cannot use the 50 W.

[RBBVNL9]

50 W input capability requires a big 50 termination resistor inside the RF frontend, plus some nice heatsink fins at the bottom of this module. There is an optional second RF generator, that sits exactly at this position. Option B95 or 96 or something like this. So whenever this second generator is present, you do not have the heatsink and therefore cannot use the 50 W.

That is indeed true. The below picture (from the video I talked about here earlier) shows the input power levels of the CMU200 on the four CMU200 inputs, and how they depend on the various options installed.

The RF1 input power depends on option B95 or B96, but also on 'option' U99 (sometimes also called B99). I put option in brackets because this one is more a downgrade than an upgrade of the instrument...

[ps]

U99 is a modification ("Umbau") required to install B95/96. This is more or less removing the heat sink. U99 is always present if you have the B95/96 option, whether it was specifically mentioned or not.

If you order U99 without adding B95/96 (why should someone do this?), it is called B99.

[RBBVNL9]

U99 is a modification ("Umbau") required to install B95/96. This is more or less removing the heat sink. U99 is always present if you have the B95/96 option, whether it was specifically mentioned or not.

Thanks for sharing that, now we know where the "U" and "B" come from ;-)

If you order U99 without adding B95/96 (why should someone do this?), it is called B99.

I also wonder why someone would do that.... But it does happen: one of my three units has B99, but does not have B95 or B96. This is the worst configuration; perhaps it was cheaper?!?

[RBBVNL9]

CMU200 as a spectrum analyzer would be the best video to do 

don't forget the use of freeres as a tracking generator.

Upon request, I now made a YouTube video on using the Rohde & Schwarz CMU200 as a Spectrum Analyzer. Actually, I made two: one as a stand-alone device and one when the CMU is used together with other software (FreRes and VMA).

In the video's I basically ask the question: "Is the CMU200 worth turning to, even if it is some 20 years old?". To do so, I put it side to side to the FPC1500, the current entry-level spectrum analyzer of R&S. As you will see in the videos, there are indeed reasons why you might want to turn to a CMU ;-) I also wonder whether people earlier in this threat called the 'missing' preamplifier' is really an issue or not. 

In the software video, I explore how Rohde & Schwarz FreRes (v5.30) and VMA Spectrum Analyzer for Rohde & Schwarz CRTU (By VMA'S SATELLITE BLOG) can significantly add to the functionalities of the CMU. Teaser: I also find some serious problems with FreRes, and started to enjoy VNA (even if it cannot exactly do what FreRes was designed for).

Enjoy, and thanks for the positive feedback I already received on the video series of the CMU!

 https://youtu.be/I_sxesKyAXE

https://youtu.be/-OL2PRv5Vhs

[_Wim_]

CMU200 as a spectrum analyzer would be the best video to do 

don't forget the use of freeres as a tracking generator.

Upon request, I now made a YouTube video on using the Rohde & Schwarz CMU200 as a Spectrum Analyzer. Actually, I made two: one as a stand-alone device and one when the CMU is used together with other software (FreRes and VMA).

In the video's I basically ask the question: "Is the CMU200 worth turning to, even if it is some 20 years old?". To do so, I put it side to side to the FPC1500, the current entry-level spectrum analyzer of R&S. As you will see in the videos, there are indeed reasons why you might want to turn to a CMU ;-) I also wonder whether people earlier in this threat called the 'missing' preamplifier' is really an issue or not. 

In the software video, I explore how Rohde & Schwarz FreRes (v5.30) and VMA Spectrum Analyzer for Rohde & Schwarz CRTU (By VMA'S SATELLITE BLOG) can significantly add to the functionalities of the CMU. Teaser: I also find some serious problems with FreRes, and started to enjoy VNA (even if it cannot exactly do what FreRes was designed for).

Enjoy, and thanks for the positive feedback I already received on the video series of the CMU!

 https://youtu.be/I_sxesKyAXE

https://youtu.be/-OL2PRv5Vhs

Nice video's!

Some comments (also posted on youtube):

For the issue with points and comma's, this could be easily fixed by Viktor if he adds the following lines when his main form is loaded:

CultureInfo newCulture = CultureInfo.CreateSpecificCulture("en-US");
Thread.CurrentThread.CurrentUICulture = newCulture;
Thread.CurrentThread.CurrentCulture = newCulture;

This forces the dotNet culture to a specific culture, and not take the culture from the OS it is running on (which is the default).

As for the Freres normalization, you should use the "repeat" button instead of "start" after a normalization. This does work correctly as far as I remember. Repeat can be used multiple times and adds additional corrected sweeps.

As for the dips in the spectrum using the VMA software, this is probably because the generator needs some settling time when switches between frequencies. If Viktor would add a configurable time the signal remains on at the same frequency, this function would work in one sweep, but the synchronous implementation of Fre-Res still seems the better approach.

[_Wim_]

As for the Freres normalization, you should use the "repeat" button instead of "start" after a normalization. This does work correctly as far as I remember. Repeat can be used multiple times and adds additional corrected sweeps.

This document has a section about using fre-res with normalization (from page 72 onwards):

https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_application/application_notes/1ma201_1/1MA201_9e_spectrum_analyzers_meas.pdf

[_Wim_]

As for the Freres normalization, you should use the "repeat" button instead of "start" after a normalization. This does work correctly as far as I remember. Repeat can be used multiple times and adds additional corrected sweeps.

This document has a section about using fre-res with normalization (from page 72 onwards):

https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_application/application_notes/1ma201_1/1MA201_9e_spectrum_analyzers_meas.pdf

Just had a quick check in the lab, with Fre-Res 5.3.0 normalize does indeed work.

In summary:
1) use the play button to measure your reference plot
2) normalize the receiver
3) use repeat to add additional normalized traces of the DUT (with the minus button traces can be deleted)
4) press "stop" to end. When the play button is now used, all traces as well as the normalization are deleted.

[RBBVNL9]

Dear all, thanks for the various replies. Indeed, I can now confirm lake others have said that FreRes normalisation does work when one uses "repeat" rather than "start". Great to know (but if this is the way the user is supposed to work, it would have been better of R&S to prevent a crash if the user did something different).

The normalisation crash was not my only issue with FreRes, however. Below is a list of particularities, issues and crashes I jotted down when trying it in the last days...

• Predictable crash when using “start” right after “normalize” (but using “repeat” instead of “start” solves that issue)
• Using ‘Level sweep’ (great for detecting linearity issues!), the program sometimes performs the measurement as expected; at other times, it does not execute the expected sweeps.
• Occasional crashes when:
            switching from ABS to REL
            activating the LOG in the sweep settings (not in the display settings)
            Using level sweep
• Setting a ‘Dwell time’ different from 0 does not seem to result in the expected pause
• “Power Measurement Error” appearing at random moments. Repeating the exact same measurement later usually results in no errors. (It might be the CMU itself, but this is hard to tell)
• The actual sweep time (left bottom) is only shown correctly after a sweep is already over. It would be great to have this as a predicting value (so, when you increase the steps by a factor of two, and select a different frequency range, the indicator could show how long that would take).
  
• When using “repeat”, earlier measurements should stay on the screen. Sometimes, I do eight measurements and they all stay. Sometimes, at the fifth measurement, the previous ones are deleted.
• Sometimes (not always), the program starts by showing “Level/dBm) on the left axis of the graph and “Rel. Level / dB” on the right side of the graph (see my video) . But after a couple of operations, the right side disappears. When both readings are there, that is nice, but when the “relative” switch is used, the right-hand side value (being relative) is no longer correct.
• Sometimes (not always) the program starts by not showing a legend on the left side of the graph at all (!)
• “Delete the last trace” (while using repeat mode) sometimes works, sometimes not.
• After a crash, the program starts with the same parameters the next time you start. You may need to change those parameters to prevent an crash again when doing a sweep.

I might have gotten some points wrong, of course, Please correct me if I did, or add if you know more ;-)

[_Wim_]

(but if this is the way the user is supposed to work, it would have been better of R&S to prevent a crash if the user did something different).

Yes, the software could certainly be much more robustly implemented and be more intuitive in use! I also believed for a very long period the normalization was not working.

• Using ‘Level sweep’ (great for detecting linearity issues!), the program sometimes performs the measurement as expected; at other times, it does not execute the expected sweeps.

When getting "min level error", this is sometimes caused by the user specifying a level outside of the limits of the selected output. But apart from that, I also have had many crashes I could not explain.

• “Power Measurement Error” appearing at random moments. Repeating the exact same measurement later usually results in no errors. (It might be the CMU itself, but this is hard to tell)

My CMU does this to. Not sure what is causing this.



With good remote software the CMU could indeed be a even more useful, but the amount of effort is quite big. I once started writing my own software, but gave up after realizing how much work it would be to achieve the features I wanted.

[Bicurico]

As the author of the "VMA Simple Spectrum Analyser Software" I would like to thank Rudi for his review.

The particular version of my software for the CMU200/CRTU has never been popular, only few people use it. I want to believe that the reasons for that are:

1) There are not that many owners of a CMU200 or CRTU
2) The ones owning such a device, don't have a Keysight USB GPIB interface (note: I have a clone from China, which cost under 100 Euro and works without any problem)
3) People don't know about my software

Anyway, the absence of many users has refrained me from correcting bugs and continuing the development beyond my personal needs.

Hopefully I can iron out some of the issues Rudi mentioned and implement Wim's tip about the Regional Settings - boy has this caused me trouble in the past and i did not know there was this simple fix. This should be presented by Visual Studio as a message box on each new project!

And yes, I do believe that any old spectrum analyser capable of outputting the swept samples in a fast way (GPIB or network) can get a new life by means of a PC software doing all the data processing. This is what I did with my software - it was not designed as a remote GUI for the device and it's particular functions but rather a new implementation of a spectrum analyser that only communicates with the hardware spectrum analyser to set fundamental parameters like START/STOP frequencies and then receives the samples.

Ideally such a software should be universal and use specific DLL's to deal with the hardware communication. I failed to build the software like this because I never expected to grow it to this state. It might be simple and a professional programmer might replicate this in a better way in little time, but it took me several years (about 7 years, if I am not mistaken) to get to the current state, where I have versions for the R&S CMU200/CRTU, HP/Agilent 859x Series, Siglent SSA/SVA, SMA/NWT/D6/LTDZ, TinySA/TinySA Ultra, Anrist SSA.

A final note about the R&S CMU200/CRTU: they are fine test equipment that offer a great spectrum analyser. However, they are still sold at a price that defies the purchase of a brand new Siglent SSA3021-P, which can be crossgraded to a SVA1032. Compared to that, the CMU200/CRTU offer a better resolution and higher sweep rates (IMHO), but they lack measurement functionality. The main concern, however, is that they suffer from several issues, which need to be named. First off, many might have a broken or out of spec RF frontend. As a consequence, the specific selftest will fail and measurements will be out of spec. This is the RF input board. But the RX/TX boards can be faulty, too. Finally the RX/TX boards come with 1x (CMU200) or 2x (CRTU) Digital Boards. These are small daughter boards. When they fail, you won't be able to repair them and they are really hard to find. Additional problems come from the PSU and the PC board. I own 5x such devices. 4 are fully working, albeit the selftest does not pass 100% on all of them. One is not fully working (bad RF input board), but usable as a SA. Then I have a case with just the main board, that has some bent pins from the previous owner. Was purchased to remove needed parts for the other 4. This is to say that I started with two broken ones to rebuild one and ended with all of these...

Kind regards,
Vitor

[RBBVNL9]

_Wim_

With good remote software the CMU could indeed be a even more useful, but the amount of effort is quite big. I once started writing my own software, but gave up after realizing how much work it would be to achieve the features I wanted.

I'm not a programmer myself, but I certainly believe writing such code, debugging, making sure it works in different environments, and maintain it over time is a significant effort. Especially for a single person doing that in his/her own time. Also for that reason, I applaud Vitor's VMA program, which is useful but also very stable.

Concerning FreRes: I'd like to believe (expect?) that a leading M&E equipment provider as R&S does have the knowledge, professionals and resources to write good software. (This program was squarely aimed at its core audience, and already in version 5.30...) 

As for using the normalisation function: both my CMU and my cables are fairly flat, and to make sure the normalisation was doing what I would expect, I did a little joke: I took a bandpass filter, normalized on that, and then did a measurement with input and output simply connected. That way, I should get the _inverse_ of the bandpass filter.

So I got what I asked for ;-)

[_Wim_]

Also for that reason, I applaud Vitor's VMA program, which is useful but also very stable.

Fully agree!

I do think one of the reasons it was not more adopted is the fact some payment was needed. We live an age where people (incorrectly) think software should be free, because they are used to that when installing apps on their phone. However, app developers typically have others ways of making revenue (typically selling your data to others), which is not viable for software like the VMA program.

This however has totally killed the market for selling software.

Concerning FreRes: I'd like to believe (expect?) that a leading M&E equipment provider as R&S does have the knowledge, professionals and resources to write good software. (This program was squarely aimed at its core audience, and already in version 5.30...) 

Fully agree here also. I guess because they offered it for free, they did not care as much as they do for their payed software. Maybe this was written & updated by thesis students? 

[RBBVNL9]

I’m having a conversation with someone whether the CMU200 actually uses FFT for its Spectrum Analyzer functionality. If it uses FFT in a ‘hybrid’ mode you would expect that its LO would jump in discrete amounts, where the jump length would be around the FFT span used at each step. Now, the relevant boards in the CMU (RXTX in particular) are very well sealed and it may be hard to get a probe there that could test that.

However, looking at the block diagram (service manual, page 3.2 , can be found here https://gotroot.ca/cmu200/CMU_Service.pdf) I see that the RXTX board has three IF frequencies (IF1 = 843.085MHz /1816.115 MHz, IF2 = 486.515MHz and IF3 = 10.7MHz), but ALSO features a bypass switch via which the entire front-end frequency band (e.g., 10MHz to 2.7 GHz) is connected straight away to the A/D converter!

Any thoughts?

[_Wim_]

Hi RBBVNL9,

Just watched your video about adding the B17 IQ IF option. As my unit has a working B17 option (it was installed when I bought the unit), I had a quick check in the setup menu. As you can see from the attached pictures, you should see a part number and modification index, so something is not correct. I would try to reinstall a firmware version with the B17 option installed.

I also attached an old pictures I had of the internal RF wiring. My unit is not loaded with as much modules as yours, but at least it gives you an idea (but the issues you are experiencing are most probably not related to the RF cables)

Hope you can get it to work, if you need additional info, please ask. 

[_Wim_]

Before doing a full firmware update, have you done this?

[RBBVNL9]

Dear Wim,

Thanks a lot! Since I finished the video session, I made considerable progress, and now I know that the problems I was experiencing were caused by at least three (!) different causes. A teaser: my problem was partially caused by wrong cabling, but I will later explain why that happened in the first place ;-) I am getting closer to resolving all and will make a video trying to summarize it in a good way so other can benefit from it.

The photo you sent on how your card shows up in the Setup menu is very interesting, however. Even after a 'firmware upgrade after board change', I still have an empty space in the field where you do have information. One possible explanation might be that I, in fact, installed the CRTU-B7 unit instead of a CMU-B17. I was not aware of this at that time, as the identification stickers were not present on my board (it seems such identification stickers are there only on units that were fitted later in time, not in units that were installed in the machine at the time of purchase)... 

Anyway, I hope to follow up soon, but thanks a lot for sharing!

[RBBVNL9]

Dear Wim,

As you can see from the attached pictures, you should see a part number and modification index,

One more follow-up... Your Setup screen reports a part number "1135.6290.03" for the IFIQ card.   

I got a bit confused there, as I remembered seeing different numbers for the CMU-B17 and the CRTU-B7 units. I quickly looked through the documentation I have here and found that for both boards, there are multiple numbers associated with them (see attached overview). R&S equipment is not only complex in terms of technology but also sometimes in terms of administration

[_Wim_]

R&S equipment is not only complex in terms of technology but also sometimes in terms of administration

That is quite surprising seeing so many different numbers for what is essentially the same thing! Quite an interesting find!

[RBBVNL9]

All,

Getting the IQIF card working in my CMU200 turned out to be no less than a quest. Basically, three things went initially wrong:
1: Errors in R&S documentation, leading me to faulty wiring,
2: CRTU-B7 is NOT equal to CMU-B17,
3: Need for “firmware update after board change”. 

I also learned quite some other things that may be relevant for CMU users, like that in specific circumstances, the instrument simply swapped the I and Q lines (!)

But now I got all up and running, and made a video documenting it.

https://youtu.be/VUljs46ViIk

[F4IUJ]

Hello,

I got myself a CMU200 for not much money. I use it mainly as a generator and a spectrum analyser. Unfortunately, I had a bit of an accident as I was using it as a signal generator to calibrate a small qrp rig VFO and I sent by error a 37dBm pulse into the front end of the CMU200 RF3 which is limited at 13dBm in my case 

I suppose that will teach me to put an attenuator even I don't think that I need one! But beyond this, is there a chance that I can repair the front end ?

Kind regards

Yannig

PS : thanks Rudy for the videos, I watch them!

[Bicurico]

If you search this forum you will find posts regarding the repair.

It involves opening up the front end module and replacing some IC's - can't remember which ones.  There are a total of 4, one for each input port.

Definitely doable, but quite some work and not totally noob-proof. For one, you are dealing with SMD components, then you need to desolder one component containing Berlium (if I recall correctly). This is why you have a safety hazard sticker on the front end module (or should have).

The white powder inside the module should just be aluminium oxide - not that dangerous. Try to vacuum clean it, but do not (as I did) blow on it...

The other option is try to buy a front-end module or a broken CMU200/CRTU. Chances are, though, that the purchased replacement is broken, also.

[Bicurico]

This is the thread I was referring to: https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-(analyzer-levels)/

Check this link of one of the posts: http://wunderkis.de/cmu200/rawpic/

It is the "C4" component you need to replace.

The RFP 50-17 AMZ component is the one you need to dessolder to get to the back of the PCB. This is the one containing berryllium: https://nj.gov/health/eoh/rtkweb/documents/fs/0222.pdf

[F4IUJ]

This is the thread I was referring to: https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-(analyzer-levels)/

Check this link of one of the posts: http://wunderkis.de/cmu200/rawpic/

It is the "C4" component you need to replace.

The RFP 50-17 AMZ component is the one you need to dessolder to get to the back of the PCB. This is the one containing berryllium: https://nj.gov/health/eoh/rtkweb/documents/fs/0222.pdf

Thank you, that is really helpful. There is one thing that puzzles me, if I see properly there is just one "C4" component but I seem to have damaged just one channel. Shouldn't it be a part specific to RF3 in my case ?

[Bicurico]

I might be wrong (long time since I looked at this), but there should be 4 such C4 components, one for each input. Two on each side of the PCB, which is why you need to dessolder the component I mentioned before.

[switchabl]

IIRC there are only two. The one for RF3 is on the top side. The one on the bottom is for RF4 and you need to desolder the attenuator and the connectors to get to that one. RF1 and RF2 don't have dedicated amplifiers.

[F4IUJ]

OK, it makes sense now...

[luc-on7kz]

Hello,
at the hamradio event I have buy a CM300, I'm not the specialist from these equipment's and has not tested completely before I buy 
ant there are issues 
first is the generator has a 3dB to low output on all the outputs and frequenties will these be a hard or software problem?? who can help me with these ??
A other fault is the message LO0Tunediag must be giving a value from 26.5v but must be between 0 and 20v I suppose these is someware a local oscillator
but don't find it direct into the (poo) service manual.
The generator and spectrum analyzer is only functioned to 2.2Ghz, readed spectrum levels are correct but not higher than 2.2Ghz
So who can help with tips/trick enz...
Greetings Luc ON7KZ

[RBBVNL9]

Luc,

Your observations suggest some problems indeed. But I'd suggest you first carry out all the self-tests (including loop 1/4 and 2/3) and relevant calibration procedures. This video may help you with some of this.

Then there is the service manual.

. rudi

[luc-on7kz]

Thanks Rudi,
having watching the video but it has notting telling me what i not know,
The service manual is poor no detailed schematics or even a more detailed blockdiagram or the place on the PCB is not to find
A lookup to the RX/TX board has also no visual issues except a small corrosion on one of the SWA filters, but where to find these parts and second problem placing these parts, I have some experience with SMD but these are just a little to high, I will not destroy the working parts.   
Any tip will be appreciated
thanks into advance
Luc On7KZ

[_Wim_]

The generator and spectrum analyzer is only functioned to 2.2Ghz, readed spectrum levels are correct but not higher than 2.2Ghz

Are you sure it is both the generator AND spectrum analyzer that are limited to 2.2GHz? I would expect it is ONLY the analyzer part. If that is the case, I would not expect it is the same corrosion issue with the filters as I had, as the filter used for >2.2GHz is also used below 1.2GHz which is working fine.

My first suspect would be a damaged RF switch (SW-239 from Maccom). Try to measure these in circuit (there a quite a few of them) and check if one of them is measuring very different with a multimeter. This could be an indication of a damaged switch.

A better (but much more work) approach is to check for each switch if a signal is seen on port A and port B when sweeping over the entire range. This however requires to solder test wires to each of the RF-switch A&B ports to be able to measure them when the unit is powered on. So I would first try to measure with a multimeter on the board itself to see if no obvious suspect is detected.

These boards have big copper planes which make it hard to remove components. So do be careful with a hot air gun as you have to add a lot of heat. As easier way in my opinion is to cut the legs of the part you want to remove with a fine cutter, and then remove leg by leg with a soldering iron. This is off course only possible if you are already sure the component in broken.

[_Wim_]

My first suspect would be a damaged RF switch (SW-239 from Maccom). Try to measure these in circuit (there a quite a few of them) and check if one of them is measuring very different with a multimeter. This could be an indication of a damaged switch.

Have a look at this post: https://www.eevblog.com/forum/repair/cmu200-rx-level-issue-failed-loop-test/msg3916070/#msg3916070

If you board looks similar, I would expect one of the two RF switches above mixer 1A & 1B might be broken. If your board looks different, it might be a good idea to try and reverse engineer like I did based on the block diagram. These boards are fairly easy to follow where the signals go, but it still takes several hours to complete...

[luc-on7kz]

Hello _Wim,
Reading and learning a lot here on these forum, your tips are great
Its so that both RX an TX fail above 2.2Ghz
The spectrum is working perfect till these frequentie, even better than my siglent SAA3021 (31) and these have i tested whit a 1Ghz signal from my R&D SMG
In the TX part i have 3dB less than it must be and these on all the outputs RF1, RF2 and RF3 i suppose somewhere a attenuator fault or ??
The search is on, I hope that it will be possible to make the CMU300 be working 100%
If that is OK than I will looking for the B41 module
greetings Luc

[_Wim_]

Its so that both RX an TX fail above 2.2Ghz

Hi Luc, in that case it is more likely that something common is broken (and thus not an RF-switch). It could be that "LO0" is used both for the RX and TX part. In my diagram I labeled LO1A and LO1B, but probably R&S labels them LO0 and LO1. As you get a tune error on LO0, this would make sense. So I would check with your SAA3021 if you get an LO signal on both mixers first.

Edit: it is very well possible the LO frequency is out of range for the SAA3021, a power meter might be a better option to check if an LO is present

Edit2: just reread my old post, the LO of mixer 1A was shared between RX and TX, so I would check this one first