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I am helping the family of a deceased friend sell his equipment. ?One item is an HP 8920A. ?I know that it was being used regularly, and it powers-up with no complaints. ?My goal is to understand the installed options so that I can ask for the best possible price.
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When powered-up, it indicates "V. A.10.11". ?Is this the hardware version or the software version? ?If software, should I try to upgrade to a later version before offering the unit for sale?
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The option and serial number tags on the back of the unit are as follows:
? ? ?001 002 003 004 005 013
? ? ?3235A02033
What does the serial number indicate?
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The self-generated option list produces the items below. ?My understanding of each is listed in parentheses. ?Did I understand them correctly?
? ? ?OPTIONAL RAM ? ? ? (256K RAM? ?What is the extra RAM used for?)
? ? ?SIGNALING ? ? ? ? ?(Tone/Digital – CDCSS, DTMF, 1-TONE and many others)
? ? ?I/O OPTION ? ? ? ? (DC Current Sensing, I/O: GPIB/RS-232)
? ? ?SPECTRUM ANALYZER ?(with tracking generator and ACP)
? ? ?HIGH STABILITY REF (OCXO high stability time base)
? ? ?C MESSAGE ? ? ? ? ?(weighted filter)
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Any help is appreciated.
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David
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It may be of little help to check all options on a unit well out of calibration and also untested. The unit would also need to pass all self tests.
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It's a heavy unit, and has an intrinsic as-is value.
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There's some who would buy it as is, and there might be mobile radio shops in your area that can test it for you or may want to buy it.
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The HP 8920A is highly desired by radio amateurs. It has been called the "Holy Grail" of test equipment. Your instrument has most of the desirable options that hams want. As long as the unit powers up and passes the self-tests, NIST calibration isn't necessary for amateur use. You can check ebay to determine an approximate asking price.
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andy? ?AE8J
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If it was a 24c I'd be offering to buy it. I'm unsure about the options and value this or that adds to the units but I have been seeing some listed $1500-$2000. But just because they are listed for that doesn't mean they sell for that. Ebay had an option to search for sold items and see how much they have sold for lately.
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VE6WMR and AE8J,
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Thank you for your responses.
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If I want to confirm that this particular 8920A is one of the earlier units with full support down to 400 kHz, is it sufficient to confirm that the signal generator will go that low?? Or are some other tests required to confirm that support?
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Thanks again.
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If it is an 8920A it most likely has the mechanical attenuator. The 8920B units have electronic attenuators. Specification for the B model are guaranteed down 10 MHz but are useable to much lower.
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On Saturday, September 14, 2024 at 06:02:21 PM EDT, David wrote:
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If I want to confirm that this particular 8920A is one of the earlier units with full support down to 400 kHz, is it sufficient to confirm that the signal generator will go that low?? Or are some other tests required to confirm that support?
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Hi David,
I have one of these instruments. I rescued it from a dumpster!. About a year later, I had it working and had learnt a lot about it in a most intimate way.
The unit has a built in test facility, accessible via the menus? by pressing "tests" button. You cannot destroy any calibrations or functions using this tests program.
There are some excellent you tube videos from various "Gurus" which would be helpful.?
There are 3 test regimes that can be selected, RF Diags, AF Diags, and MS Diags. You select say RF diags and press enter by pushing the rotary knob in when the RF DIAGS word is highlighted. The thing is quite slow to load the program, you will see the letter 'R' and 'L' flashing in the upper right corner of the screen, this is the program loading the software module to perform the tests. (Read and Load).
Follow precisely the instructions on the screen. From the pull down menu, select "All Tests" and follow the prompts, which includes attaching a coaxial cable from one BNC to another. RF In / out to Duplex In, for example.
The program will evoke the various functions and internal switching to measure literally hundreds of measurements. If there is a failure, the program will flag them and there will be a beep.
You can crack the Champaign when the final result displays "All RF Tests Passed".
The other two tests are similar. The AF tests involve connecting the AF out at the back panel to the AF In (Hi) at the front panel.
Results should be "All AF Tests Passed".
MS Diags is a test of the power supply and the cable.
If all the tests pass, you have a unit that is within specification. It will be, as mentioned by others, "The Holy Grail."
Parts are hard to find and software is getting impossible.?
I have had great support from Amtronics in USA.
A lot of support can be had from this Forum too.
Best of luck
Bill M.?? VK6IC.
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That 8920a will go down to 400 khz
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There are software applications available on Sram cards that turn the test set into a powerful automated diagnostic tool. North American FM Tests, HP 11807 Option 001 includes a quick test feature that tests 20 receive and 20 transmit points of any FM transceiver. When connected to a printer through HPGIB or the RS-232 serial interface a hard copy record of test results can be produced. Being somewhat portable (40 lbs) makes it easy to do presentations at your local ham radio club. Additionally, the HP 8920a has the ability to allow you to develop your own custom testing procedures using the built-in IBASIC compiler.
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Andy, AE8J
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If you are in the mainland USA and want a hassle free sale contact Rick at Amtronix ( ).
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He specializes in these instruments. He will offer a fair price, probably more than an ebay auction.
Your friend's unit has, as others have said, all the desirable options [the only better option for amateur use is a 8920B with the mechanical attenuator (400kHz) option].
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Good luck,
Robert
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* Andy: I confirmed that:
- the RF Generator produces a nice sine wave down to (at least) 100 kHz
- the Spectrum Analyzer correctly displays an externally-generated, modulated AM signal at 400 kHz
- the RF Analyzer correctly interprets an externally-generated, modulated AM signal at 400 kHz
So yes, it would seem to have the mechanical attenuator.
Thanks for the tips on additional diagnostic tools.
* Bill/VK6IC: Thanks for the info about the built-in tests. ?I ran all three suites.
- RF Diags
This did not ask me to make any connections. ?Perhaps it is because the unit has an earlier firmware version?
In any case, 2 tests failed in the "Output Variable Attenuator", "Suspect: Input Assembly (High)". ?See photo.
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All other tests in this suite passed.
- AF Diags
This suite did ask me to make connections, which I did. ?All tests passed.
- MS Diags
This suite has 3 tests. ?Two passed. ?The third requires an external 10 MHz reference. ?I don't own one so I just ordered one.
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* Robert/G8RPI: ?Thanks for the info about Amtronix.
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David, AK2L
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I have one with 001,002,003,004,005 and I researched greatly to find one with these options.? It has everything you need for Ham use and is even more than I need for the 2-way customers I service.? Most have the standard 60 watt input limit.? There were also options for much lower maximum input.? It is good to use an external attenuator anyway so you don't burn your baby.?
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This was an upgrade from my IFR and the monitors at work.? I am semi retired and only do Analog systems, but I used to calibrate the modulation in digital stations as well.? It has no usable trunking features for the latest encrypted trunking systems but I sought this one for its ability to operate down to 400 kHz and HF SSB service as well as FM systems.? And the kicker is the 002 Tracking option for aligning duplexers and the High stability oscillator 001 is what I was also looking for to take care of 800 MHz systems.? It is also able to be checked out and calibrated without expensive and proprietary codes and keys.? There is ample information in the files section of this group and on the internet, even to do repairs if you dare.?
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All the advice given so far is good and Amtronics is a good place to start with looking up the features and some tips for operation.?? Mine has ver A14 firmware and it might be useless to update yours unless the hardware can support it and make use of it.? If I remember correctly, firmware was for production changes and some programming syntax,? and options that became standard and some of the option numbers changed because of this. There are 2 different documents out there for the A models that list different option numbers and modules.? The giveaway is the option 002 Spectrum analyzer, mine has tracking but no ACP? but it may have been added later.? Later models had an option 102 spectrum analyzer with tracking and ACP but I don't know if your firmware supports it.? The rest you have right.? In any case you could take the cover off and see the part numbers on the modules to see what is really there. ? The later model A and B, went to a solid state switched attenuator that didn't perform well on lower frequencies and had reliability problems, and a new board to support PCMCIA memory cards.? Note that for some module replacements, you will require the factory PCMCIA or Sram card with calibration data for that module.
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The internal memory is for operation of the unit and to save custom setups and programs so you can recall them from a list you have saved.? Cats meow!? There are external memory cards sort of available, that are the same as Epson 40 pin Sram cards that were used for voting machines, calculators and printers.? They are in the $100 plus range and you will spend many hours or days to find them at that reasonable cost.? The down side is that you have to change the battery every 6 months while the card is plugged into the unit, or the memory in the card is lost.
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This family of service monitors has the capability of being married to various hardware in a production or automated shop, and can be programmed in HPBASIC for a complete testing routine that can produce a report on the unit under test.? These tests can be from the card, the instrument's memory or remotely via GPIB link.?
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Mine was about $2000 on ebay 5 years ago.? When you advertise it take good photos and show the display with the options and self-test passed.? Most buyers will assume that if it isn't powered up, it doesn't work or the screen is dying.? These were often lovingly guarded in the lab while the grunts in the field lugged around older heavier monsters that got beat up.? Someone said that it is heavy, but is the lightest I have used except for an FM/AM 1000S I used in the 70s.? People still search for the FM/AM 500 even though it rediculously bare bones, because it is small and light and makes a good movie prop.? There are a whole bunch of used monitors out there that are lighter and cheaper, but have features that are for obsolete or specific tasks and are useless to many.? I was dismayed to find that many don't even have a high stability timebase.?
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Jim
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Hi Andy, I am interested in your comment about using the compiler in the HP8920A.
Tell me more ... What do I need to get into this? Can I interface my Windows 7 or 10 to talk to the HP ? I do have RS232 I/F option on my 8920A, and an OKI RS-232 Printer.
Any links to software programs I would need?
Regards
Bill M.? VK6IC
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Hi David,
Some comment on doing the tests. Offered in good faith.
Be sure to allow perhaps 1 hour with the unit on, to get a stable Internal oscillator before performing the test routines.
Use a good quality Coax Cable for the rf tests. I think my unit asks me to connect RF IN/OUT to Duplex in, and does a quick test to determine the attenuation of the test cable, this is then applied to the test regime to avoid cable losses. An intermittent cable will be? great problem.
It is interesting that the figures on your results have low values. I will check my notes from my travels through the beast last year. I seem to remember that I have seen this fault before. I did clean the edge connectors with a proprietary electronic cleaner, and make sure the PCBs are seated well. The 255 value seems OK , I am not sure if that is fully attenuated or a through connection ( No Attenuation)
It may be that the DAC concerned actually has a faulty component. Perhaps try to output some RF of a certain value and measure with another level instrument. I.E. your ham receiver "S" meter, after doing a clean and inspection. I take notes when working on My HP, noting what I did and when, plus the Results / Changes . Thus I can look back at the notes and check if I had this problem in my unit, and what I did to fix it.
I bought a GPSDO on ebay, it works very well.
Regards
Bill M? VK6IC
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Hi Bill,
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Here are three links to HP manuals pertaining to IBASIC that will get you started.
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73,
AE8J
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Andy -
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The hard part is creating a program and somehow getting it into the analyzer.
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I just uploaded a file - App Note 8920-1.pdf - that goes a long way toward explaining this process.
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It would be good to get this into a more simplified explanation, with more clearly explained steps, but I don't have the time at the moment.
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If someone gets it working well, perhaps they can write up their procedure details for the rest of us.
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John K.
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Jim: Thanks for the info and advice.
When G8PRI mentioned Amtronix, I knew something was familiar about that name, but couldn't put my finger on it. ?Then when I looked at Amtronix's web site I remembered that I had purchased a nice return loss bridge from them at Hamvention 2014.
I have lots of screen photos, some of them with captions. ?So that should prove to a prospective customer that the unit is indeed working.
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Bill/VK6IC: ?Thanks again for your comments.
The unit had been on for a while when I first ran the RF Diags suite. ?It reported 3 errors, not 2. ?I let the unit run overnight and ran the suite a couple times more. ?The third error never reappeared.
I like your idea of re-seating the PCBs. ?(Reminds me of a Macintosh I had years ago. ?About every 6 months I had to reseat the memory modules or the computer would randomly crash due to memory errors!)
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On Tuesday, my GPSDO should arrive. ?I'll re-seat the boards and run the frequency test and let you know what I get.
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David, AK2L
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John,
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I'm using an old Windows XP laptop. I made a custom RS-232 serial cable to communicate between the HP8920A and the laptop.?I have an old Thinkjet printer connected with HPIB. I don't think the HP Basic software runs on newer versions of Windows. Here is a link to Amtronix website for downloading the HP BTS screen capture utility.
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73,
AE8J
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On Monday, September 16, 2024 at 12:59:35 PM EDT, j.kernkamp@... wrote:
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Andy -
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The hard part is creating a program and somehow getting it into the analyzer.
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I just uploaded a file - App Note 8920-1.pdf - that goes a long way toward explaining this process.
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It would be good to get this into a more simplified explanation, with more clearly explained steps, but I don't have the time at the moment.
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If someone gets it working well, perhaps they can write up their procedure details for the rest of us.
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John K.
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All good Dave.
Bill M.? ?VK6IC
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Jim: Thanks for the info and advice.
[snip for brevity]
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Bill/VK6IC: ?Thanks again for your comments.
[snip for brevity]
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On Tuesday, my GPSDO should arrive. ?I'll re-seat the boards and run the frequency test and let you know what I get.
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David, AK2L
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If you have strong signals from the local TV stations, The ATSC pilot carrier is usually network tied to GPS and I see them within a couple of hertz of each other here.? Have to have a pretty strong signal to calibrate from the input though.? Look it up and you will see the standard is much less than 1 Hz (although some may be required to offset to avoid interference).
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You have to almost find the old HP computer that can run and debug the HP BASIC, but the instrument can debug whatever you upload to the instrument as text.? Kind of like throwing it against a window to see if it sticks.
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The instrument has 2 rs-232 ports and can be used to feed instructions into the instrument, then run the program and catch output to the printer or a text file.? I did run the setup dump program found in the files section and it ran perfectly (but slow).
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The next nightmare you will run into, is A model saves setup screens in LIF internally but somehow saves to DOS in the card if it is fornatted that way.? I was hoping to back them up to a hard drive and fill the card and/or machine so I don't lose them in the card to a dead battery.? The programming manual is kind of a tease and I don't have time to reverse engineer the whole syntax and command structure.? The answer may be to hack up an Epson card R/W for the computer, or run a program in the machine to file manage with a terminal program in the computer.
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