Marconi 2022 RF Generator

[xrunner]

Does anyone here have any experience with one of these? I'm looking at some on Ebay and from the specs they seem to fill my need for an RF generator. But I'd like anyone's input if they have ever used one. Used ones are going for something like ~$450 - $600.

Thanks.

[Andy Watson]

I have the 2022E. It's my favourite RF generator. But, they are early implementations of Marconi's digital synthesis design - it has spurs that are relatively high and sometimes close-in to the carrier. Also, the 10MHz processor clock throws out a lot of noise.

[xrunner]

I have the 2022E. It's my favourite RF generator. But, they are early implementations of Marconi's digital synthesis design - it has spurs that are relatively high and sometimes close-in to the carrier. Also, the 10MHz processor clock throws out a lot of noise.

K thanks. I just bought the "D" version off Ebay, likeness as shown below. 

[philpem]

Also watch out for failures of the OM345s and faulty switches. You can get "drop-in" replacement modules from ebay (or scrape off the ceramic from the bad part and solder in a 3k9 resistor if you're a cheapskate).

Look out for failures in output levelling, attenuation not working correctly, AM/FM modulation not working, frequency being wrong, often at the frequency cut points (if I remember correctly these are 62.5MHz, 250MHz, 350MHz and 500MHz - check the service manual!). If you do 50 or 100MHz steps from 10MHz to 1GHz and test AM/FM mod at both, you should be able to get pretty decent test coverage. Then just set it for CW and check that both the 1dB steps (done with AM/levelling circuitry) and 10dB steps (done with a step attenuator) work.

Sadly doing a proper test on one of these pretty much requires a spectrum analyser or a set of RF power meter, modulation meter and 1GHz frequency counter. You may be able to sub a general-coverage receiver for a modulation meter if you only care about a general "does it work or not", but you definitely need to make sure that at 0dBm indicated, you're getting 0dBm out.

Trap for new players: these units don't check the ALC loop voltage like most Agilents do. If the ALC runs off into the weeds, you don't get an "UNLEVELLED" error!

When mine blew an OM345 (causing loss of levelling and AM above 350MHz) I ended up spending a week fixing a UUT which wasn't actually broken, only to plug the SG into my spec-an and find it was 8dB down at 350MHz and got progressively worse as the frequency increased...

I have a 2022E. I've heard the standard 10MHz ref is shockingly bad, but I don't find it too bad. I've been known to mate it to my Racal 1991 (which has a homebrew OCXO reference) if I'm doing anything which requires ppm-level-or-better frequency stability.

Out of curiosity -- does anyone know what Marconi changed in the different versions? (2022, D, E, etc.)
It doesn't seem like there's much to choose between them.

Cheers,
Phil.

[xrunner]

Sadly doing a proper test on one of these pretty much requires a spectrum analyser or a set of RF power meter, modulation meter and 1GHz frequency counter. You may be able to sub a general-coverage receiver for a modulation meter if you only care about a general "does it work or not", but you definitely need to make sure that at 0dBm indicated, you're getting 0dBm out.

Thanks for the info. I don't have a spec-an yet but I do have a very good freq counter and certainly many receivers so I will do as best a check as I can with that stuff. The seller has a lab and a lab tech guy who has performed a check of the unit. Couldn't I (at somewhat lower frequencies) dump the output into a 50 ohm load and look at the PP V on a scope? For example at 0 dBm it's 1 mW into 50 ohms which should be 632 Vpp on the scope.

Out of curiosity -- does anyone know what Marconi changed in the different versions? (2022, D, E, etc.)
It doesn't seem like there's much to choose between them.

I actually talked to the seller on the phone yesterday (it's actually a test equip remarketing Co.), and I asked him that very question! The reason I called was because the lady (secretary) that wrote up the description said it had a GPIB option, but the pics didn't show that option, so I wanted to clear that up. He said he didn't know what the the model designators signified either. There was an "A" model and a "D" model for sale on Ebay, and I decided on the "D" model since it had a higher letter, so I presume it's ... um ... more betterer in some way. 

[KJDS]

I can't remember the details, but I think there are only minor improvements and possibly maximum output power increases across the models. I'm sure anyone really concerned could trawl the web for the different specs but I doubt there's any significant changes.

They are good basic instruments and much smaller than most other offerings with that level of performance.

[PA0PBZ]

For example at 0 dBm it's 1 mW into 50 ohms which should be 632 Vpp on the scope.

O0     

There was an "A" model and a "D" model for sale on Ebay, and I decided on the "D" model since it had a higher letter, so I presume it's ... um ... more betterer in some way.

AFAIK It has (also) to do with the different modulation options, like more than 1 tone and external in/output

[G0HZU]

I like the little 2022 as well. I've been using these generators for many years at work. They are great if you don't have much bench space and you just need to generate a simple signal.

The spectral purity isn't that great on them but they are a good little workhorse. However, I do think they are overpriced on the used market UNLESS you specifically need the small size and portability.

The other slight downside is that the user interface lacks rotary controls so it you want to wiggle the frequency you have to press the up/down buttons. On some examples the button system can be worn out or damaged making some commonly used buttons annoyingly deaf or intermittent. GPIB is a useful bonus and this would allow remote operation and the option to do soft rotary controls.
The LCD display can sometimes go a bit washed out or intermittent as well.

[philpem]

I like the little 2022 as well. I've been using these generators for many years at work. They are great if you don't have much bench space and you just need to generate a simple signal.

The spectral purity isn't that great on them but they are a good little workhorse. However, I do think they are overpriced on the used market UNLESS you specifically need the small size and portability.

On the UK used market, just about all signal generators are "overpriced"... same as most test gear our "dealers" (in some cases I use the term "overpriced scrap merchants") attempt to sell

My 2022E was actually the cheapest I could find -- I wanted a 2024 (I think that's the right P/N -- the one Dave reviewed... a 19in rackmount thing with a backlit graphical LCD) but they were going for far more than I wanted to spend. I found a GPIB-enabled 2022E for a few hundred Euros on eBay Germany and paid about 30 Euros to bring it back to England

The other slight downside is that the user interface lacks rotary controls so it you want to wiggle the frequency you have to press the up/down buttons. On some examples the button system can be worn out or damaged making some commonly used buttons annoyingly deaf or intermittent.

True enough, and the switches (I think they're called ISOSTAT switches though my memory may be failing me on that) have been discontinued for some years and are thus a pig to find. I've got a handful of spares on hand for my own use keeping my 2022 running.

GPIB is a useful bonus and this would allow remote operation and the option to do soft rotary controls.
The LCD display can sometimes go a bit washed out or intermittent as well.

The LCD is actually a fairly easy fix. Strip the front panel and remove the PCB, then disassemble the LCD (carefully!) and clean the PCB-side LCD contacts with one of those PCB polishing blocks (the brown things that look like a pencil rubber). Use a clean lint-free cloth and some isopropyl to clean off the 'shavings' from the polishing block. Reassemble and test.

I like the GPIB remote control idea. Could be a good way of getting some more mileage out of a unit with a dead front panel as long as you know (or can set) its GPIB address. I usually just use it for automated testing...

Cheers,
Phil.

[G0HZU]

On the UK used market, just about all signal generators are "overpriced"... same as most test gear our "dealers" (in some cases I use the term "overpriced scrap merchants") attempt to sell

My 2022E was actually the cheapest I could find -- I wanted a 2024 (I think that's the right P/N -- the one Dave reviewed... a 19in rackmount thing with a backlit graphical LCD) but they were going for far more than I wanted to spend. I found a GPIB-enabled 2022E for a few hundred Euros on eBay Germany and paid about 30 Euros to bring it back to England

I guess what I was trying to say was that the 2022 offers very little in the way of (modern) performance yet it often sells for a third to a half of the price of something like a 2024.

IMO the key to success when buying generators (on an individual basis)  is to know when and where to look. Nearly two years ago I bought an HP/Agilent  ESGD 4GHz vector sig gen with some options fitted as an ex rental from a large UK TE rental company (one of the biggest). They have regular clearance sales.

It cost under £800 and came with a nearly new 2 year calibration from Trescal.

I bought another 4GHz Agilent E4433B for £1000 that had all the top options fitted from a well know UK dealer including the dual arb and real time baseband option. It was just before year end (or xmas) and I negotiated a good price for cash It has all the common digital mod options fitted internally eg BPSK, QPSK QAM and all the mobile phone formats etc etc and this must have cost well over £20k new yet was a third of the age of a typical 2022. I bet if the same dealer had a 2022 for sale it could have been for >>£350.

I also bought a Marconi 2024 maybe 5 years ago for £800. I actually bought three of them for £800 each from the same dealer (who had loads and loads of them to sell quickly)  but I sold two of them them on at cost to a friend. All three had the top options fitted including the hi stability oven and +25dBm power. The one I kept had only 120 hours run time and looked brand new

The other alternative to the 2022 is the big old Marconi 2019(A). They tend to sell quite cheaply and they offer similar performance to the 2022. But they are big and heavy and arguably less reliable that the (already unreliable?) 2022.

[xrunner]

Thanks for all the advice on the Marconi 2022's

Also watch out for failures of the OM345s and faulty switches. You can get "drop-in" replacement modules from ebay (or scrape off the ceramic from the bad part and solder in a 3k9 resistor if you're a cheapskate).

I've studied these failures and downloaded some notes and images in case any of the OM345s fail. As I have read it appears a resistive trace can go bad, and I see how the SMD resistor can fix it. I'll be ready to go if that happens, but hopefully it won't. If I'm not satisfied I have 14 days to return for a full refund, but it's been checked out by a lab tech so I'm not too worried.

The unit is supposed to be here next Tue so will do as many checks as I can across the freq. range and maybe post some pics. 

[TheDefpom]

I use the 2022d and found it fine, never had any issues.

Prior to that I used to TF2015 with the TF2171 synconizer, work fine but drifted slightly, I actually had an ic fail on that, located on a board above the crystal oven, the heat was going straight to the ic, but I managed to find spares and repaired it, still have a few ics tucked away, and still have the unit as a backup in case the 2022d dies.

[G0HZU]

Thanks for all the advice on the Marconi 2022's

Also watch out for failures of the OM345s and faulty switches. You can get "drop-in" replacement modules from ebay (or scrape off the ceramic from the bad part and solder in a 3k9 resistor if you're a cheapskate).

I've studied these failures and downloaded some notes and images in case any of the OM345s fail. As I have read it appears a resistive trace can go bad, and I see how the SMD resistor can fix it. I'll be ready to go if that happens, but hopefully it won't. If I'm not satisfied I have 14 days to return for a full refund, but it's been checked out by a lab tech so I'm not too worried.

The unit is supposed to be here next Tue so will do as many checks as I can across the freq. range and maybe post some pics. 

It was me that did the research work for this some time ago on another forum. A forum member sent me a dead OM345 and I looked at it under a microscope after I'd removed the outer coating. I suggested two ways to fix it. Either scrape and fit the correct value piggy SMD resistor across an existing capacitor or the lazy option is to just fit a 4K7 resistor across pin 1 and 5. i.e. across the input pin and the output pin of the OM345. The 4K7 method isn't exactly an elegant repair but it would be OK as a quick/temporary solution in some cases

[xrunner]

It was me that did the research work for this some time ago on another forum. A forum member sent me a dead OM345 and I looked at it under a microscope after I'd removed the outer coating. I suggested two ways to fix it. Either scrape and fit the correct value piggy SMD resistor across an existing capacitor or the lazy option is to just fit a 4K7 resistor across pin 1 and 5. i.e. across the input pin and the output pin of the OM345. The 4K7 method isn't exactly an elegant repair but it would be OK as a quick/temporary solution in some cases

Indeed I did see your name pop up - good work.

Does anyone knwo what these sold for new back in the day?

[KJDS]

It was me that did the research work for this some time ago on another forum. A forum member sent me a dead OM345 and I looked at it under a microscope after I'd removed the outer coating. I suggested two ways to fix it. Either scrape and fit the correct value piggy SMD resistor across an existing capacitor or the lazy option is to just fit a 4K7 resistor across pin 1 and 5. i.e. across the input pin and the output pin of the OM345. The 4K7 method isn't exactly an elegant repair but it would be OK as a quick/temporary solution in some cases

Indeed I did see your name pop up - good work.

Does anyone knwo what these sold for new back in the day?

I'll take a guess at £2000

[xrunner]

Got it today- so far all checks have shown good. Will do a little clean up of the case and front panel. 

[artag]

I've got a 2022 (no suffix). The output's not very flat and the buttons suffer the problem described above but it's good enough for my needs at the moment. I understand the 2022E was a cost-reduced version for some big mil contract so if later is better, your 2022D is probably the best of the bench. Or get a 2022E and an external reference.

Mine didn't have the HPIB option but I recently found an ebay seller in Israel with some 2018/2019 HPIB boards pretty cheaply. Electrically they're very similar and I think I'll be able to hack it in without too much trouble. Mechanical fitting will be more of a challenge but I think it will go between top and bottom halves of the internal boards. This is above the digital board and outside the RF screens so probably won't hurt performance much.

[xrunner]

I've got a 2022 (no suffix). The output's not very flat and the buttons suffer the problem described above but it's good enough for my needs at the moment. I understand the 2022E was a cost-reduced version for some big mil contract so if later is better, your 2022D is probably the best of the bench. Or get a 2022E and an external reference.

Thanks for the info. So far I'm pretty damn pleased with it. What I did today was to check the S-meter calibration on a shortwave radio - an FRG-7700. According to the IARU (the International Amateur Radio Union) the level at the antenna terminals required for an S9 reading is -73 dBm. I set up the 2022 for -73 dBm on 29 MHz and fed it into the radio. I was very surprised that the S meter actually read S9. I wasn't surprised that the Marconi put out the right level, but that the radio's S-meter was that well calibrated. 

[xrunner]

Does anyone know where to obtain the cooling fan replacement? Mine's working but it sometimes makes a little noise. I looked in the register that contains the total amount of hours the unit has been on and it's 108156 which is equal to 12.3 years. I'd like to replace the fan. The parts list shows it to be a "Fan Ax 5V DC 48 MM". If I can't find a replacement I'll attempt to lube it - I've done that with older computer fans.

[xrunner]

I sourced a replacement from Mouser. It's not the exact same one but it has the exact case and mounting hole dimensions. Should be OK.

[xrunner]

[Marconi 2022D fan replacement]

Well nothing is so simple ...

I got the new fan installed and hooked up, turned on the unit, and the fan did not run. After sitting there in amazement I futzted with it a bit and it started to run but not very well. I measured the voltage at the supply pins and it was only 4V. But with the fan disconnected it was 5V.

What is wrong? It's just a simple fan that runs @ 5V, 150 mA. 

I looked at the Marconi schematics and found that the +5V supply to the fan goes through a small inductor. When I connected the old fan, it still ran and the supply voltage was 5V. Apparently the current draw on the old fan is so small that it doesn't cause a voltage drop across that small inductor, but 150 mA is enough to drop about a volt. I can find no other reason for this behavior.

So that fan is out. I found another Micronel fan like the original on Ebay, but the part number is a little different, and the case does not have the holes tapped for the original screws. I asked the seller about the part number and he said the only difference he could find was that the wires ran out the side of the case, and this could easily be changed, so I ordered that fan.

What I'm going to do is pop-out the fan motor and the part that holds it in the case and then pop it into the old case so I can mount it. As you can see in the pic the whole thing is a press-fit, and comes out if you tap it out. Now I wait for the next fan to arrive ...

[Mr Helpful]

2022C was a higher power output version of the 2022A
There was no 2022B.
2022E was a military version of the 2022C with a downgraded xtal osc.
2022D was the white version of the 2022C and had a different modulation frequencies - otherwise the same.
Marconi changed their colour scheme.

Hope it helps

[david69]

Hello, The Marconi 2022A RF Unit AB1/1 missing power output transistor MRF587?
oposite Marconi 2022C otherwise is unit simillar?

[robbie1949]

I have the RF 2022 and RF 2022C, the 2022C has a bit different electronics and I guess there are small differences in all of the letter prefixes.  To start the 2022 used 4 x 8K (27C64) eproms for the firmware while the 2022 uses only one a 27C512. After reading the data burnt into  the chip only 32K of the 64K available is used.  I have backed this up as a file and will post it soon.

[Astralix]

Hey guys!

First of all thanks for all the details hidden in this thread!
I'd like to push up the topic again, as I got a 2022C for my hobby lab. My old generator is a HP 8660C with Modulation and 1300MHz plugins. But even I think that the 2022C does not support sweeping, it has two major benefits: It needs 25W compared to the 200+W the 8660C draws and you can still listen to radio, while it runs

I checked mine against a frequency standard, and could pull the internal reference to be +/-0.01Hz off at 10MHz. But I use it mostly with an external ref supplied.
Also I found, that the three frequency ranges had their output levels way off, except for the 500..1000MHz rang. But I was able to fix that without any problems by using the 2nd level menu function 15. But reading the hints above, I'll test the complete attenuator chain later.

One question I have is, what firmware is the most recent for these devices. Mine shows 010 as a version. I will open, clean and probably re-cap the unit in near future, so I also will pull and dump the EPROMs for safety. Also a real calibration is pretty straight forward, as the service manual is very nicely made.

CU
Ulrich