Author Topic: HP 8753 VNA - C/D differences and LCD Upgrade  (Read 10064 times)

0 Members and 1 Guest are viewing this topic.

Offline TheSteve

  • Supporter
  • ****
  • Posts: 3743
  • Country: ca
  • Living the Dream
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #25 on: April 16, 2019, 09:52:19 pm »
Fire it up and measure something!  :P
VE7FM
 

Offline dmills

  • Super Contributor
  • ***
  • Posts: 2093
  • Country: gb
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #26 on: April 16, 2019, 10:03:56 pm »
My '47A has a black tag on the lefthand connector indicating that it is designed to move to take out tolerances in test fixtures, this was very standard on HP gear.

Regards, Dan.
 

Offline SpencerTC

  • Contributor
  • Posts: 34
  • Country: us
  • Curious mind
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #27 on: April 18, 2019, 08:24:30 pm »
If you are still wanting a CPU board, I have several 8753's (most of which are 75Ω, but the CPU board is the same) and if you like, I would be glad to copy the EEPROM (which includes the correction) over to the new board too, offer me a fair price and I'll let you know.

p.s. no idea if they are the newer processor board or the old one, if you are still interested in that I'll have to check on that first.

Best regards,
Trent Spencer - KM4YTU
 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #28 on: April 23, 2019, 05:56:48 pm »
Fire it up and measure something!  :P

I did just after I got the APC7 adapters last week  ;)
Works pretty well, as far as I can tell.

I have no cal kit (yet) so I made one real quick from SMA edge launch connectors - credits to qls.net and Claudio Girardi's DIY cal kit tutorial - and then measured them on a calibrated VNA, used Claudio's octaves script to get the cal. coefficients and tried to use it as a cal standart. Not entirely happy with the results yet. Not sure if I messed up the calibration on the 'reference' VNA or if I have to thinker with the script / starting parameters some more... One error I noticed was removing the teflon insulation on the 'open' standard, which changed the impedance to ~60Ohms. Also the delay on the throu might be off by a bit...

Attached some plots + raw data of a comparison between a MiniCircuits 6db attenuator measured with both VNA's - HP8732's measurement exported as .s2p via floppy disk :-DD






« Last Edit: April 23, 2019, 05:59:46 pm by sixtimesseven »
 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8573 VNA - Version C vs. D
« Reply #29 on: April 23, 2019, 06:24:01 pm »
8753D all day long for me, especially because it has the newer/faster CPU(confirmed by firmware 7.74). With an interface box you can use ecal units with it.

Hi Steve

Do you happen to know if the 85097B interface box and the 85093C ecal module would be directly compatible with the 8753D with firmware 6.14?
 

Offline TheSteve

  • Supporter
  • ****
  • Posts: 3743
  • Country: ca
  • Living the Dream
Re: HP 8573 VNA - Version C vs. D
« Reply #30 on: April 23, 2019, 08:04:15 pm »
8753D all day long for me, especially because it has the newer/faster CPU(confirmed by firmware 7.74). With an interface box you can use ecal units with it.

Hi Steve

Do you happen to know if the 85097B interface box and the 85093C ecal module would be directly compatible with the 8753D with firmware 6.14?

Assuming you have an Ecal menu under Cal I'd guess yes, but can't say for certain. Finding information is tough, I'd check on the Keysight network analyzer forum.
I've also been experimenting with characterizing cal kits. In my case I am working on a 26.5 GHz 3.5mm kit with no data. I have had pretty good results so far verifying a proper Keysight kit so I am on the right track. I am using Metas VNA tools.
It would be nice to find some low cost SMA parts that are easy to buy that we could have some values for that would generally perform well to 3 or 6 GHz.
VE7FM
 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #31 on: April 23, 2019, 08:22:23 pm »
Quote
It would be nice to find some low cost SMA parts that are easy to buy that we could have some values for that would generally perform well to 3 or 6 GHz.

I was a bit surprised that the DIY cal kits projects are all from a couple years back and there was just one available tool readily available for finding cal. coefficents from s-parameters (from qls.net).

If you had some spare time, a description of your Metas Workflow would be great! That software package is not intuitive...


I havent checked for 3.5mm parts which I guess would be expensive on their own, but checking on Digikey there are open / short and load sma caps available. One of the shorts even mentions "reference short" as a use case - No data though... Have you tried those yet?
 

Offline Bud

  • Super Contributor
  • ***
  • Posts: 6877
  • Country: ca
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #32 on: April 23, 2019, 09:57:13 pm »
Low cost SMA cal kits are here:

https://www.sdr-kits.net/calibration-information-for-DG8SAQ-VNWA-3-3EC

They claim having their cal standards characterized, so you can verify your test results against what they provide.
Facebook-free life and Rigol-free shack.
 

Offline rfspezi

  • Regular Contributor
  • *
  • Posts: 173
  • Country: 00
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #33 on: April 24, 2019, 07:24:23 am »
I did just after I got the APC7 adapters last week  ;)
Works pretty well, as far as I can tell.

May i ask where you bought the adapters?
 

Offline hendorog

  • Super Contributor
  • ***
  • Posts: 1617
  • Country: nz
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #34 on: April 24, 2019, 07:49:22 am »
Remember if you can measure any old diy standard on a calibrated vna then you have all the information you need to use that cal standard on your vna to make accurate measurements.

The problem is that DIY cal standards are usually  not good enough to be well modelled well over a wide bandwidth. And old vna require a model of the standard instead of using the measured data of the standard. So there are two options:
Do the calibration on a PC where the cal standards are represented by s1p data instead of the modelled data. E.g. metas vna
Or create multiple models of the standards, each covering a limited bandwidth. These can be a good fit when the frequency range is limited. The model data can be entered into the vna and used normally without a PC.

Or of course you can use a wideband model and just accept the residual errors.

 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #35 on: April 24, 2019, 08:17:29 am »
I did just after I got the APC7 adapters last week  ;)
Works pretty well, as far as I can tell.

May i ask where you bought the adapters?

I got a pair of Ebay from Germany...
 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #36 on: April 24, 2019, 10:18:02 am »
Remember if you can measure any old diy standard on a calibrated vna then you have all the information you need to use that cal standard on your vna to make accurate measurements.

The problem is that DIY cal standards are usually  not good enough to be well modelled well over a wide bandwidth. And old vna require a model of the standard instead of using the measured data of the standard. So there are two options:
Do the calibration on a PC where the cal standards are represented by s1p data instead of the modelled data. E.g. metas vna
Or create multiple models of the standards, each covering a limited bandwidth. These can be a good fit when the frequency range is limited. The model data can be entered into the vna and used normally without a PC.

Or of course you can use a wideband model and just accept the residual errors.

Well I was looking at the scikit-rf calibration function which looks interesting.
However, I have not figured out yet how to save S-Parameters on floppy disk on the uncalibrated 8753. I can enable the save data array option but it does not generate a .s file  ???
 

Online KE5FX

  • Super Contributor
  • ***
  • Posts: 1878
  • Country: us
    • KE5FX.COM
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #37 on: April 24, 2019, 06:33:12 pm »
Remember if you can measure any old diy standard on a calibrated vna then you have all the information you need to use that cal standard on your vna to make accurate measurements.

The problem is that DIY cal standards are usually  not good enough to be well modelled well over a wide bandwidth. And old vna require a model of the standard instead of using the measured data of the standard. So there are two options:
Do the calibration on a PC where the cal standards are represented by s1p data instead of the modelled data. E.g. metas vna
Or create multiple models of the standards, each covering a limited bandwidth. These can be a good fit when the frequency range is limited. The model data can be entered into the vna and used normally without a PC.

Or of course you can use a wideband model and just accept the residual errors.

Well I was looking at the scikit-rf calibration function which looks interesting.
However, I have not figured out yet how to save S-Parameters on floppy disk on the uncalibrated 8753. I can enable the save data array option but it does not generate a .s file  ???

I'd suggest getting a National Instruments adapter (the GPIB-USB-HS works well) and running VNA.EXE instead of messing with the floppy drive.  But then I'm biased. :)

In all seriousness, a VNA becomes 10x more useful with PC software support, especially if you need to use it professionally.  You will also be able to run Calkit Manager, for instance.
 
The following users thanked this post: sixtimesseven

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #38 on: April 24, 2019, 06:37:51 pm »
Quote
I'd suggest getting a National Instruments adapter (the GPIB-USB-HS works well) and running VNA.EXE instead of messing with the floppy drive.  But then I'm biased. :)

In all seriousness, a VNA becomes 10x more useful with PC software support, especially if you need to use it professionally.  You will also be able to run Calkit Manager, for instance.

I have an gbib-usb-hs and I used the calkit manager to upload my diy cal kit coefficents but I was not yet aware of vna.exe - Looks awesome, thank you!
 

Offline TheSteve

  • Supporter
  • ****
  • Posts: 3743
  • Country: ca
  • Living the Dream
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #39 on: April 24, 2019, 07:19:51 pm »
Screen captures via GPIB:
https://www.keysight.com/main/software.jspx?ckey=360519&lc=eng&cc=US&nid=-11143.0.00&id=360519

They aren't the best but still it is very useful.
VE7FM
 
The following users thanked this post: Sparky49, DrNefario

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - Version C vs. D
« Reply #40 on: April 27, 2019, 11:21:01 am »
I had always planned to do a post on how I did the LCD mod to my 8752C but never got around to it. I have since sold the 8752C but I still have notes on the mod.
I used a LED backlit 8 inch 1024x768 LCD screen with a VGA driver - $50 shipped from ebay
The 8752C video signal was converted to VGA using a GBS-8200 - $17 shipped from ebay
The stock CRT is powered by 65 VDC so I used a 120 VAC to 12 volt adapter that happily worked with the 65 VDC input to power everything.
The stock video driver has separate horizontal and vertical signals that need to be joined together for the GBS-8200 to sync, that is done using 2 gates of a 74AC86 XOR in DIP format. The AC version is used so it can be powered by the 3.3 volt supply on the GBS-8200.
The stock backlight in the LCD I used was a little weak and driven well under spec so I powered the LED backlight from the 12 VDC supply through 15 ohms of resistance.
The above mods let me keep all changes in the CRT unit only which is easily removed and connected only by a single ribbon cable.
The boards were mounted to a piece of copper clad that was cut to fit on the bottom of the original CRT cage.
The LCD adjustment button PCB was mounted on the top of the CRT cage - they are only used once for the initial setup, same with the buttons on the GBS-8200. Once setup the top cover of the CRT cage is screwed in place.
Here are two pictures, a top view looking into the CRT cage after the mod was done and of the LCD mounted with the original tinted shield glass installed.
I was very pleased with how it turned out. I wouldn't doubt the newscope LCD is even nicer but this mod was very affordable and still looks/works great.

Any questions let me know.

edit - added the correct schematic of the sync combiner I used.


Steve

Do you still have the schematic / pinout of the video header?
There seems to be no schematic available from the HP8753D, at least not in the service guide and I have not found anything more :(

I'm also trying to get the arcade converter to work with the BNC outputs on the back. But as far as I can see there is no sync output available whatsoever(?)
 

Offline TheSteve

  • Supporter
  • ****
  • Posts: 3743
  • Country: ca
  • Living the Dream
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #41 on: April 28, 2019, 04:56:22 pm »
There is sync on the rear BNC jacks, it is just integrated into the green video. To separate it out I used an LM1881. The example circuit from the datasheet works just fine.
You can get the schematic for your 8753D on ko4bb's website - http://ftb.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent
You want - Agilent_8753D_Network_Analyzer__Service_Manual-8753DCLIPmanual.pdf
VE7FM
 
The following users thanked this post: sixtimesseven

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #42 on: May 14, 2019, 09:32:24 pm »
My HP8753 CRT to LCD conversion is finally finished ;D

I used this LCD:
https://de.aliexpress.com/item/HDMI-VGA-AV-Control-Fahrer-Bord-8-zoll-HE080IA-01D-1024-768-IPS-high-definition-LCD/32922514189.html?spm=a2g0s.9042311.0.0.220d4c4dQZQILY
And this CGA Converter:
https://de.aliexpress.com/item/Games-video-converter-CGA-EGA-YUV-TO-VGA-signal-2VGA-OUTPUT-GBS8220/541420074.html?spm=a2g0s.9042311.0.0.220d4c4dQZQILY
The 65V to 5V converter is a Meanwell SD-15C-05:
https://uk.farnell.com/mean-well/sd-15c-24/converter-dc-dc-15w-24v/dp/1299033

Thanks to TheSteve's kind help & his HV to S combiner circuit (see post #17)
Pinout for the HP8753 CRT connector is printed on the CRT board (see attached picture).

For the converter CGA to VGA converter board have a look at:
https://www.mikesarcade.com/estore/datasheets/GBS-8200-booklet.pdf

Important note:
My picture was drifting from ok to red in about two minutes. The solution was to adjust in the GBS8220 menu:
St clamp 03 and Sp clamp to 04 (default 95 and 85) which solved that problem.

I played around with some settings but apart from horizontal / vertical adjustments found the defaults to give good results for now.

For the LCD attachment I used mate vinyl foil cut to size with my Shilouette cutter (file attached) on the front of the glass and some rough vinyl cuts on the back to get rid of reflections from behind. The screen is fixed with conductive copper tape - the expensive 3M EMV stuff which gives great adheasion.

The LCD menu is accesible via the infrared sensor trough the ventilation holes on the side which is nice.

Cost is really competitive compared to the NewScope option and conversion is pretty simple.
« Last Edit: May 14, 2019, 09:40:08 pm by sixtimesseven »
 

Offline sixtimessevenTopic starter

  • Frequent Contributor
  • **
  • Posts: 330
  • Country: ch
    • Flickr
Re: HP 8753 VNA - C/D differences and LCD Upgrade
« Reply #43 on: May 14, 2019, 09:33:24 pm »
More pics:
 
The following users thanked this post: TheSteve


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf