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Re: HP 8920A spectrum analyser amplitude calibration
¿ªÔÆÌåÓýHi George, ? It is reading around 10% low, compared to the HP438, measured at 1W and 20W, 50MHz. ? I have not got as far trying to cal this, but again there is no obvious method. ? Rgds ? Colin ? From: [email protected] [mailto:[email protected]]
On Behalf Of george edmonds via groups.io
Sent: 13 April 2020 23:56 To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP 8920A spectrum analyser amplitude calibration ? Hi All On Monday, 13 April 2020, 22:28:37 BST, Colin Smithers <colin@...> wrote: ? ? Thank you Robert and everyone else replying. I am collecting all the suggestions and working out which route to take, or whether its simpler to just keep on entering the offset or just remember the error as I have been doing. ? But most of all I am filled with simple disbelief that this instrument was left so incomplete in self-cal capability, unless it is just well hidden, in which case why is it so well hidden? ? The point about it being close so it¡¯s very wide spec is the soft option, as the error is VERY constant, across frequency, time and temperature. I think it could hold +/- 0.5 dB if done properly. The instrument reminds me of the schoolchild that ¡®could do better, if only he would only try¡¯. A few decades ago I used a different Spec An that was wonderfully calibrated. Then it went off for cal and on return the horizontal span cal was miles out; signals near the edge of the screen were almost 10% off. I complained and the answer came back from the 3rd party test lab ¡®its within spec¡¯. But someone had fiddled as it was not like that previously. However, that is another story. ? Keep it coming, as its also crystal clear that I am far from not alone with this problem. ? Kind regards to everyone. ? Colin ? From: [email protected]
[mailto:[email protected]]On Behalf Of Robert G8RPI via groups.io ? Good timing, see latest message from Jeff on the HP 8924 Family group. He;s written some code to do it via RS232 :-) |
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Re: HP 8920A spectrum analyser amplitude calibration
Hi All Don;t want to distract from the excellent replies, BUT what about this line in the original posting. "Also trying to calibrate the power meter. I have a calibrated HP438 power meter to guide me" WHAT ARE THE POWER METER ERRORS? George G6HIG. On Monday, 13 April 2020, 22:28:37 BST, Colin Smithers <colin@...> wrote: Thank you Robert and everyone else replying. I am collecting all the suggestions and working out which route to take, or whether its simpler to just keep on entering the offset or just remember the error as I have been doing. ? But most of all I am filled with simple disbelief that this instrument was left so incomplete in self-cal capability, unless it is just well hidden, in which case why is it so well hidden? ? The point about it being close so it¡¯s very wide spec is the soft option, as the error is VERY constant, across frequency, time and temperature. I think it could hold +/- 0.5 dB if done properly. The instrument reminds me of the schoolchild that ¡®could do better, if only he would only try¡¯. A few decades ago I used a different Spec An that was wonderfully calibrated. Then it went off for cal and on return the horizontal span cal was miles out; signals near the edge of the screen were almost 10% off. I complained and the answer came back from the 3rd party test lab ¡®its within spec¡¯. But someone had fiddled as it was not like that previously. However, that is another story. ? Keep it coming, as its also crystal clear that I am far from not alone with this problem. ? Kind regards to everyone. ? Colin ? From: [email protected] [mailto:[email protected]]On Behalf Of Robert G8RPI via groups.io
Sent: 13 April 2020 22:08 To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP 8920A spectrum analyser amplitude calibration ? Good timing, see latest message from Jeff on the HP 8924 Family group. He;s written some code to do it via RS232 :-) |
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Re: Bill West keytop puller
On 4/13/20 6:29 PM, Roy Thistle wrote:
As to deoxit being bunkum: I disagree.WTF? -- Dave McGuire, AK4HZ New Kensington, PA |
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Re: Bill West keytop puller
On Mon, Apr 13, 2020 at 08:43 AM, Chuck Harris wrote:
As to deoxit being bunkum: I disagree.Well... a man convinced against his will is of the same opinion still... and as the forum gods know... too well.. this topic has been liberally discussed... even? ad nauseam. Hence... I will only say, "When DeoxiT tries to convince with hokum, bunkum, and swill, Roy is of the same opinion still. Best regards and wishes. Roy |
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Re: Bill West keytop puller
Dave McGuire wrote on 4/13/2020 12:25 PM:
Hello--Fader lube is wonderful for resurrecting pots of all kinds.Yes. And their gold wipes are fantastic for gold-plated card-edge Here's my adventure with the springs in Bill West switches: I wound up using shim stock (0.002 inch thickness) and made replacement springs by snipping out suitably-sized pieces. 73-- Brad? AA1IP |
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Re: HP 8920A spectrum analyser amplitude calibration
¿ªÔÆÌåÓýThank you Robert and everyone else replying. I am collecting all the suggestions and working out which route to take, or whether its simpler to just keep on entering the offset or just remember the error as I have been doing. ? But most of all I am filled with simple disbelief that this instrument was left so incomplete in self-cal capability, unless it is just well hidden, in which case why is it so well hidden? ? The point about it being close so it¡¯s very wide spec is the soft option, as the error is VERY constant, across frequency, time and temperature. I think it could hold +/- 0.5 dB if done properly. The instrument reminds me of the schoolchild that ¡®could do better, if only he would only try¡¯. A few decades ago I used a different Spec An that was wonderfully calibrated. Then it went off for cal and on return the horizontal span cal was miles out; signals near the edge of the screen were almost 10% off. I complained and the answer came back from the 3rd party test lab ¡®its within spec¡¯. But someone had fiddled as it was not like that previously. However, that is another story. ? Keep it coming, as its also crystal clear that I am far from not alone with this problem. ? Kind regards to everyone. ? Colin ? From: [email protected] [mailto:[email protected]]
On Behalf Of Robert G8RPI via groups.io
Sent: 13 April 2020 22:08 To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP 8920A spectrum analyser amplitude calibration ? Good timing, see latest message from Jeff on the HP 8924 Family group. He;s written some code to do it via RS232 :-) |
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Re: HP 8920A spectrum analyser amplitude calibration
¿ªÔÆÌåÓýAnd the Marconi 2955,2965 & 2945 series family are all still in strong use.(Marconi was first to market the radio test set in the form we recognise today) Regards Nigel From: [email protected] <[email protected]> on behalf of Robert G8RPI via groups.io <robert8rpi@...>
Sent: 13 April 2020 21:03:31 To: [email protected] <[email protected]> Subject: Re: [HP-Agilent-Keysight-equipment] HP 8920A spectrum analyser amplitude calibration ?
The HP 8920A may be obsolete but it is still supported by Keysight in the UK (and USA)
Worth asking them for a price, it might not be as bad as you think, fully automated calibration is cost effective. Calibration is no problem, repair is subject to parts availability. Still lots of these in use. Analog radio isn't dead yet. Demand is strong enough that Keyight sell a 8920A "clone" the M8920A. Basically a bunch of PXI modules and software. R&S still sell plenty of the CMU500 too. Robert G8RPI. |
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Re: HP 8920A spectrum analyser amplitude calibration
The HP 8920A may be obsolete but it is still supported by Keysight in the UK (and USA)
Worth asking them for a price, it might not be as bad as you think, fully automated calibration is cost effective. Calibration is no problem, repair is subject to parts availability. Still lots of these in use. Analog radio isn't dead yet. Demand is strong enough that Keyight sell a 8920A "clone" the M8920A. Basically a bunch of PXI modules and software. R&S still sell plenty of the CMU500 too. Robert G8RPI. |
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Re: Opens and shorts for 4285A LCR meter owners
On Mon, 13 Apr 2020 at 20:20, Tam Hanna <tamhan@...> wrote:
When I get some labels on them, I will send some photographs. I will also send a photograph of the 4285A, as the photo of the 4284A could confuse someone into thinking you need the opens and shorts for cable compensation of the 4284A, which you do not.? The two instruments look identical though. The 4284A, all the lower frequency models and the higher frequency 4295A need opens and shorts for fixture compensation. But they are quite simple. Only the 4285A needs the additional ones I made, which is for cable compensation. On of the lower frequency models, you just set the cable length. I expect that's good enough for use to 1 MHz, but on the 30 MHz 4285A, which two stages of compensation are needed. * Cables * Fixtures |
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Re: Bill West keytop puller
¿ªÔÆÌåÓý¡°help wash the grease that HP so foolishly used, out from under the springs.¡¯Actually, I disagree... remembering that much of this kit is now working much longer than the makers probably intended ( good?!), so what they designed in as a process in manufacture has probably ensured these fine instruments are still here for us to use (repair) and enjoy... You might call it long term maintenance - the switch lifetime is well in excess of what was expected. Let¡¯s not complain. Regards From: [email protected] <[email protected]> on behalf of Chuck Harris <cfharris@...>
Sent: 13 April 2020 15:43:14 To: [email protected] <[email protected]> Subject: Re: [HP-Agilent-Keysight-equipment] Bill West keytop puller ?
On this, I have to completely agree:? There is no cause to
remove the key caps from these keyboards to clean any part. The keycaps become essentially welded on after a quarter century.? Where they may have pulled off easily when they were new (if you used the manufacturer sanctioned puller), now, things break. The best way I have found to service these keyboards is to wash them liberally with IPA.? Liberally, meaning soaking, dripping wet over a pan. I use a pump sprayer filled with IPA over a pan to collect the wash.? I soak every part of the key mechanism, while pressing the key multiple times to help wash the grease that HP so foolishly used, out from under the springs. After a thorough wash, I shake, and then blow off the remaining IPA. No lubrication is necessary, or even desirable.? None.? Don't do it. If a spring has taken a set, just bend it back to straight, and put it back. As to deoxit being bunkum: I disagree.? It improves the contact, and does so for a long, long time.? I am not saying that something else wouldn't work... show me something better. The makers do get needlessly huckstery about their product. Fader lube is wonderful for resurrecting pots of all kinds. -Chuck Harris Roy Thistle wrote: > On Sun, Apr 12, 2020 at 02:05 PM, Maurice Smulders wrote: > >> >> What is the safest way to pull the keytops of a Bill West keyboard? I have >> a 3325A and 8131A with sticky keys I want to fix... > > AT >>From 3:10 to 5:08... Curious Mark pulls the caps off a 3325A Bill West keyboard... and shows cleaning and lubing (with DeoxiT... which I think, DeoxiT is mostly bunkum). There is a shot of the tool he is using (looks like a small nail puller) at exactly 4.03/15:18. > Seems a bit brutal... He tore the plunger out of the 7 key's frame! (...you can see that if you watch closely.) > If you look in the comments you'll see? Raymond Domp Frank's? recommendations (...same as he has posted in this thread.) > Best regards and wishes. > Roy |
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Re: Retrofit of a back-light to 3457A LCD
Good idea - thanks!
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Quoting Martin Rickes <MRickes@...>: Hi everybody, |
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Retrofit of a back-light to 3457A LCD
Hi everybody,
some time ago there was a quite interesting discussion about the LCDs on the 3457 and similar. The meters are nice, but annoying to read, if the room-light is a bit dim. I managed to retrofit some kind for back-light to my meter without changing anything on the unit itself. I added it to my homepage for better documentation, I hope nobody minds just posting the link :) Please do not expect a "proper" backlit display. I think this is impossible to archive because of the construction of the display-module. But it is a helper and definitely an improvement over absolutely no light. Best Regards, Martin |
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Re: GPSDO connected to external ref inputs
Thanks, Frank. Jim
------ Original Message ------
From: "Frank Mackowick via groups.io" <fpmacko@...>
Sent: 4/13/2020 10:55:53 AM
Subject: Re: [HP-Agilent-Keysight-equipment] GPSDO connected to external ref inputs The output of my x10 dist amp was running at about +12 dBm driving two radios and seven TE.? I put a 10dB pad on the input side because my Icom IC-9700 was complaining about the high level.? e.g.,?? Your +10 dBm is about 5 dB higher than normal practice but definitely won't hurt anything even if not mitigated. |
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Re: 5343A troubles
Um, Daniel, the high frequency input says 500 MHz to 26.5 GHz, so expecting it to work much below 500 MHz is a bit much.? I checked my 5343A with an 8350B sweeper with 83592B plug-in (10 MHz to 20 GHz), and got it down to 200 MHz at 0 dBm working just fine.? Got dicey at 100 MHz and 0 dBm, though.? I've not checked at lower input levels but could do so if you think it would help you. I haven't tried the lower frequency range lately.? Just back a few years ago when I got it to make sure it worked.? AFAIK, mine works fine.? I can't go beyond 20 GHz (not yet!). Jim
------ Original Message ------
From: "Daniel Sheen" <danielsheen5@...>
Sent: 4/13/2020 5:59:33 AM
Subject: Re: [HP-Agilent-Keysight-equipment] 5343A troubles
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Re: 4195A question
Hey friends
sorry for my late reply. But the last few days it has been such nice weather that I spent most of my time outside and was not hanging out in my home lab :-) and also didn't check the emails too frequently. So my apologies for that, but I didn't forget this thread. I can share the Python source code as soon as I have a more readable version of it. The current one is quite ugly I must say. But I sent messages off-list to some of you. |
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Re: Opens and shorts for 4285A LCR meter owners
¿ªÔÆÌåÓýHello, and it's off:
With best regards Tam HANNA Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at On 2020. 04. 13. 2:41, Dr. David
Kirkby, Kirkby Microwave Ltd wrote:
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Re: GPSDO connected to external ref inputs
That's 4 Volts peak to peak unterminated. 2 Volts peak to peak or +10 dBm into 50 ohms, which I assume the 5343A and 8566A have.
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As to radiation, not as far as I know. I've not tried to work the HF band that I hear gets obliterated by stray 10 MHz from distribution systems. Unless one takes care with double shielded coax and terminators on all unused outputs. Not there with the ham radio gear yet (will take recommendations on a 70 cm capable rig, though). Thanks. Jim ------ Original Message ------
From: "Bruce" <bruce@...> To: [email protected] Sent: 4/13/2020 9:25:03 AM Subject: Re: [HP-Agilent-Keysight-equipment] GPSDO connected to external ref inputs No problem - I do think 4v is a bit high though - any radiation problems? |
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Re: GPSDO connected to external ref inputs
The output of my x10 dist amp was running at about +12 dBm driving two radios and seven TE.? I put a 10dB pad on the input side because my Icom IC-9700 was complaining about the high level.? e.g.,?? Your +10 dBm is about 5 dB higher than normal practice but definitely won't hurt anything even if not mitigated.
best regards.... Frank Mackowick / WA3NHK |
Dave McGuire
Jared Cabot
Dr. David Kirkby, Kirkby Microwave Ltd
Martin Rickes