Re: Semiconductor test set advice
Yeah, complete UI/UX changes with web services seem to be par for the course these days. Farcebook is a leading example. But I digress...
Another thing to keep in mind with the Tek curve tracers is some of them develop HV transformer difficulties (lots of info about this+repair strategies on TekScopes); however, they are indispensable if you need to characterize high power parts. The 575 with a particular special option (name and number escapes me) is even better for this. I'd personally like to find a good one with that option as it would be a great curve tracer and would satisfy the itch to have one glowing Tek with vacuum tubes and ceramic strip construction. :o) It doesn't have blanking though, so things like families of curves will show retrace unlike a 577 or 576. The 577 also has the advantage of basically being made of standard 5000 series oscilloscope parts, unlike the 576 which is large and more complicated with the fiber optics to light the display annunciators. You can also get the 577 with a storage crt, but whether that crt will have any life left is questionable most likely.
As I understand it, the semiconductor parameter analyzer that HP marketed was really more intended to be an analytical lab instrument mainly focused on characterizing lower-power parts, while Tek curve tracers often were used on production lines for matching components and stuff like that. This at least partially explains why a lot of 577 and 576 curve tracers that come up for sale are beat up pretty badly. And as you observed, good condition examples command high prices.
I understand where you are coming from wanting to be able to do whatever measurement you need. I'm working to build up to that and also be able to calibrate my own stuff. Perhaps we can have a discussion offline about what you've found indispensable, as I believe our interests align quite a bit in the microwave realm.
Cheers!
Sean
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On Mon, Apr 27, 2020 at 07:02 AM, Reginald Beardsley wrote:
Occulus, Thanks. Yahoo changed the interface so that it doesn't show unread messages in the SPAM bin :-(
As a consequence I've been forgetting to check and empty it as I used to do every day.
I do wish that "developers" would realize that people do *not* want the UI to change constantly.
Keysight didn't have much on their stuff on the website, but I eventually found copies of the manuals at some of the repair shops. It appears that a 4145B is what I want (i.e. is cheap enough I can afford it ). Perhaps augmented by a Tek 576 or 577, but those look rather expensive and hard to find.
In general I want to be able to make pretty much any test I might need. At the time I was most active designing and building stuff all I had was a 5 MHz recurrent sweep single channel scope (banana plug input), a VOM and a DMM. All my other test gear was DIY. Trying to build radios from scratch with that is pretty much a lost cause. But I was in my early 30's on my 2nd pass through grad school. So I had no budget for things other than books. Those were very expensive, though now it appears to be worse.
Reg
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Anyone from HP that worked on the design of the 1700 Series Scopes?
I am trying to find details on parts used in the design of the 1703A and the 1707B. Specifically
the FET's used in Option 20 the Vertical Output Amplifier. These would be matched FET's HP Part number 1855-0085.
These parts are not found in the cross reference so it would be good to know what the base part number is and it someone might
know what the matching parameters are.
I would like to clone this board (an perhaps make a wider bandwidth one) so having additional info on it would be great.
I have the schematics for both of the designs that were used the one from the 1707B OPT 300 military scope and one from the 1703A.
The 1707B one used a 2N4044 matched NPN? in a TO-78 can followed by a pair of 2N3906's. The 1703A one uses a matched pair
of N-Channel JFETS followed by a PNP/NPN for output drive with a 741 op-amp. It's a clever design for the time using the op-amp for the
DC path and using AC coupling for the high frequency (such as it was then) path.
In any event finding the original parts in any quantity would be a problem so a re-design that uses modern parts would be better. I have already completed a
PCB layout for the 1707B version using the original parts which got me thinking that others may want one as well so that led me to be thinking about something
using modern op-amps, etc.
So I am hoping that some there are some members of the group that worked on these scopes.
Thank you,
Sam
W3OHM
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Re: How to check the accuracy of an HP 5342A frequency counter
FWIW General Radio in the instructions for one of its early frequency measuring assemblies recommended the "three oscillator" method of measuring differences. Where a source is being compared to WWV the third oscillator can be the BFO in the receiver. The BFO is set for an audio beat and the waxing and waning of the beat from the other two can be heard plainly. It is possible where the signals are steady to detect and measure fractional cycle beats this way. Since your standard runs on a WWV frequency it should be trivial to determine if its on frequency. Since you have three measuring instruments all showing the same approximate error I rather think the standard is off. If its adjustable you can likely get it closer using this method.
?? My understanding from long ago is that a rubidium oscillator is used mainly as a filter to eliminate phase noise from a cesium clock.
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On 4/27/2020 8:22 AM, Edward Newman via groups.io wrote: First, make sure the Rb standard is locked. Second, couple the output of the Rb to a receiver and check it against WWV. ?Adjust the coupling so that the Rb signal is about the same strength as WWV. You should be able to detect errors of a few Hz pretty easily. Even without a recent cal the Rb standard, if locked, should be better than 1Hz at 10 MHz. ?If the standard checks out you can then adjust the ref oscillator in each counter to read exactly 10 MHz on the counter.
However, I'm betting there is a problem with the standard, since all the counters show the same error.
Remember all these Rb standards were pulled because they were pretty worn out. I had one stop locking, and now have two, checked against a GPSDO. ?I can set mine to about .001 Hz against the GPSDO.
Finally, after using the Rb for a while I realized that none of the internal ref oscillators are as stable as the Rb, so I just feed the counter the Rb as a reference. Since I got my Rb reference GPSDO have gotten a lot less expensive, so if your Rb is misbehaving I'd suggest buying one of those.
Ed. W2EMN
On Apr 26, 2020, at 10:34 PM, Terry Maurice <ve3xtm@... <mailto:ve3xtm@...>> wrote:
I have two of these units, one has the oven the other does not.? The two units do not read exactly the same value when fed with a signal from a 10MHz FE-5680A, rubidium frequency standard.? I am monitoring the frequency standard with the two HP units and my Siglent SSA 3021X spectrum analyzer, all units being fed from the rubidium standard through a Downeast Microwave 10-4, 10MHz amplifier and filtered 4-way divider. The units have been on for about 5 hours before taking the readings below.
Unit A (with crystal oven) reads 9,999,828 Hz, +/- 2 Hz; unit B reads 9,999,830 Hz, +/-2 Hz and my spectrum analyzer reads 9,999,826 Hz.? Are these values within the expected values for these older frequency counters?? Is the FE-5680A correct? I checked both HP 5342As with their internal references and both show 10MHz.? How can I know, which unit(s) are correct, or do I assume my rubidium frequency standard is off by about 170 Hz?
The FE-5680A does generate some heat when left on for prolonged periods, however, It is mounted on an aluminum heatsink and sealed inside a solid metal box, but the metal case is only slightly warm to the touch.? On my oscilloscope, the output of the rubidium standard shows a distorted wave, but once it passes through the DEM 10-4 it is a clean sine curve.
Any help or comments would be much appreciated.
Terry
--
Richard Knoppow
dickburk@...
WB6KBL
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Re: How to check the accuracy of an HP 5342A frequency counter
First, make sure the Rb standard is locked. Second, couple the output of the Rb to a receiver and check it against WWV. ?Adjust the coupling so that the Rb signal is about the same strength as WWV. You should be able to detect errors of a few Hz pretty easily. Even without a recent cal the Rb standard, if locked, should be better than 1Hz at 10 MHz. ?If the standard checks out you can then adjust the ref oscillator in each counter to read exactly 10 MHz on the counter.? However, I'm betting there is a problem with the standard, since all the counters show the same error.? Remember all these Rb standards were pulled because they were pretty worn out. I had one stop locking, and now have two, checked against a GPSDO. ?I can set mine to about .001 Hz against the GPSDO. ? Finally, after using the Rb for a while I realized that none of the internal ref oscillators are as stable as the Rb, so I just feed the counter the Rb as a reference. Since I got my Rb reference GPSDO have gotten a lot less expensive, so if your Rb is misbehaving I'd suggest buying one of those.?
Ed. W2EMN
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On Apr 26, 2020, at 10:34 PM, Terry Maurice < ve3xtm@...> wrote: I have two of these units, one has the oven the other does not.? The two units do not read exactly the same value when fed with a signal from a 10MHz FE-5680A, rubidium frequency standard.? I am monitoring the frequency standard with the two HP units and my Siglent SSA 3021X spectrum analyzer, all units being fed from the rubidium standard through a Downeast Microwave 10-4, 10MHz amplifier and filtered 4-way divider.? The units have been on for about 5 hours before taking the readings below.?
Unit A (with crystal oven) reads 9,999,828 Hz, +/- 2 Hz; unit B reads 9,999,830 Hz, +/-2 Hz and my spectrum analyzer reads 9,999,826 Hz.? Are these values within the expected values for these older frequency counters?? Is the FE-5680A correct? I checked both HP 5342As with their internal references and both show 10MHz.? How can I know, which unit(s) are correct, or do I assume my rubidium frequency standard is off by about 170 Hz?
The FE-5680A does generate some heat when left on for prolonged periods, however, It is mounted on an aluminum heatsink and sealed inside a solid metal box, but the metal case is only slightly warm to the touch.? On my oscilloscope, the output of the rubidium standard shows a distorted wave, but once it passes through the DEM 10-4 it is a clean sine curve. ?
Any help or comments would be much appreciated.
Terry?
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Wanted: HP 8445b Preselector
hi,
Wanted: HP 8445b Preselector .
Please contact me off-list.
thank you,
rick
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Re: How to check the accuracy of an HP 5342A frequency counter
Thanks Chuck for that information.? I suspect that my rubidium reference may be on the old side.? I bought it used over 8 years ago and I used it a fair amount as a frequency reference for my Flex 5000A, when I had that rig operational.
The locked light does come on after a few minutes of operation.
And thanks to all for the comments and suggestions.? I will work through them and see what I find.
Terry
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On 2020-04-27 7:47 a.m., Chuck Harris wrote: Atomic references are in general, short lived. Cs beam's run
out of vacuum, or out of Cs (some debate about that!). Rb
references plate out the Rb metal on the lamp's glass bulb,
and get to a point where not enough light can get past the
plated out Rb metal film for the detector to operate.
The Rb can very often be fixed when the lamp goes dark by using
a heat gun to evaporate the Rb on the inside of the bulb where
the light is emitted, and let it plate out somewhere else.
The biggest problem is gaining access to the Rb bulb. Many
of the compact units are essentially assemble only devices.
When either a Cs beam standard, or a Rb reference runs out of
"physics" to operate, its disciplined VCXO will end up against
its rails too high, or too low in frequency (depending on how
it was designed).
Also, crystal ovens are a reliability problem. They are
electrically heated devices, and as such must be protected
against thermal runaway situations... lest they catch fire.
[I have seen oven failures where the entire oscillator board
melted its solder, and parts dropped out.]
In many cases, the thermal fuses installed inside of the oven
will fail, even though there is nothing otherwise wrong with
the oven. But again, they are usually assemble only devices,
and replacing the fuse will require serious removal efforts.
-Chuck Harris
Dr. Frank wrote:
I fully agree to Ed Breya. Your Rb standard very probably is not locked, 17ppm off is a typical sign for that.
All such OCXOs (10544 or 10811) can never be out that far, if they are operating correctly (i.e. getting warm, please check).
As both OCXO agree to each other, they seem to be working.
Please check the LOCK signal of your Rb clock.
After you identified the root cause, further hints how to correctly adjusti either of your clocks can be given.
Frank
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Re: Semiconductor test set advice
Occulus, Thanks. Yahoo changed the interface so that it doesn't show unread messages in the SPAM bin :-(
As a consequence I've been forgetting to check and empty it as I used to do every day.
I do wish that "developers" would realize that people do *not* want the UI to change constantly.
Keysight didn't have much on their stuff on the website, but I eventually found copies of the manuals at some of the repair shops. It appears that a 4145B is what I want (i.e. is cheap enough I can afford it ). Perhaps augmented by a Tek 576 or 577, but those look rather expensive and hard to find.
In general I want to be able to make pretty much any test I might need. At the time I was most active designing and building stuff all I had was a 5 MHz recurrent sweep single channel scope (banana plug input), a VOM and a DMM. All my other test gear was DIY. Trying to build radios from scratch with that is pretty much a lost cause. But I was in my early 30's on my 2nd pass through grad school. So I had no budget for things other than books. Those were very expensive, though now it appears to be worse.
Reg
|
Re: How to check the accuracy of an HP 5342A frequency counter
Atomic references are in general, short lived. Cs beam's run
out of vacuum, or out of Cs (some debate about that!). Rb
references plate out the Rb metal on the lamp's glass bulb,
and get to a point where not enough light can get past the
plated out Rb metal film for the detector to operate.
The Rb can very often be fixed when the lamp goes dark by using
a heat gun to evaporate the Rb on the inside of the bulb where
the light is emitted, and let it plate out somewhere else.
The biggest problem is gaining access to the Rb bulb. Many
of the compact units are essentially assemble only devices.
When either a Cs beam standard, or a Rb reference runs out of
"physics" to operate, its disciplined VCXO will end up against
its rails too high, or too low in frequency (depending on how
it was designed).
Also, crystal ovens are a reliability problem. They are
electrically heated devices, and as such must be protected
against thermal runaway situations... lest they catch fire.
[I have seen oven failures where the entire oscillator board
melted its solder, and parts dropped out.]
In many cases, the thermal fuses installed inside of the oven
will fail, even though there is nothing otherwise wrong with
the oven. But again, they are usually assemble only devices,
and replacing the fuse will require serious removal efforts.
-Chuck Harris
Dr. Frank wrote:
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I fully agree to Ed Breya. Your Rb standard very probably is not locked, 17ppm off is a typical sign for that.
All such OCXOs (10544 or 10811) can never be out that far, if they are operating correctly (i.e. getting warm, please check).
As both OCXO agree to each other, they seem to be working.
Please check the LOCK signal of your Rb clock.
After you identified the root cause, further hints how to correctly adjusti either of your clocks can be given.
Frank
|
Re: How to check the accuracy of an HP 5342A frequency counter
I fully agree to Ed Breya. Your Rb standard very probably is not locked, 17ppm off is a typical sign for that.
All such OCXOs (10544 or 10811) can never be out that far, if they are operating correctly (i.e. getting warm, please check).
As both OCXO agree to each other, they seem to be working.
Please check the LOCK signal of your Rb clock.
After you identified the root cause, further hints how to correctly adjusti either of your clocks can be given.
Frank
?
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Re: Maximum depth of HP rack mountable gear?
Avoid IKEA. Much of their furniture is hollow on the inside, especially the worktop desk surfaces. El Wife found that out painfully when drilling...
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 27. 3:21, Jim Ford wrote: Yeah, don't discount kitchen DIY furniture as found at places like IKEA. ?The wife and I redid our computer/music/scrapbooking room with kitchen cabinets rather than the office stuff about 7 years ago. IKEA had way better selection in the kitchen department than in the office department.? The office stuff they offered was really lame!? Of course now with the Corona Virus and working from home, my laptop computers and desk area get a lot more use!
Jim Ford
------ Original Message ------
From: "Tam Hanna" <tamhan@...>
To: [email protected]
Sent: 4/24/2020 10:55:02 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Maximum depth of HP rack mountable gear?
Wife introduced kitchen work surfaces (Kuechenarbeitsplatte). Cheap, can be had at home improvement store, works well here.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
On 2020. 04. 25. 7:50, John Parkins G8KVP wrote:
Hello Dave,
No nothing bad at all, just making it more difficult for ourselves.
When we moved house I took over a room for my gear, so I was able to
build benches, shelves etc as I wanted them. At first it was fine, but
I think as we all do a flat surface is for putting things on. So the
amount of available work area reduces and reduces until we're trying
to work on a large bit of gear in a space which isn't quite big
enough...... I've over come this by having a removable 'bench' which
is only put into place when I need the extra room and removed
afterwards. If it were left in place it would end up covered in stuff!
We can't help it, I think it's in all our natures to collect.
Friday, April 24, 2020, 6:53:46 PM, you wrote:
DM> On 4/24/20 12:27 PM, John Parkins G8KVP wrote:
WORKBENCH! How ever wide you make them they just aren't wide enough.
DM>?? Unfinished flat doors make very good workbenches. And desks, for that
DM> matter.
Why do we do this to ourselves?
DM>?? You say this as if there's something bad about it.
DM>???????? -Dave
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Re: RMS voltmeter HP 3400A - what does option C61 stand for?
Thanks, Jeremy,? Sean,
Mine has C61 as well and it's no different from non-C61 version visually or in performance.
Leo
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Re: How to check the accuracy of an HP 5342A frequency counter
The rubidium should be the most accurate of the bunch, except for the GPSDO. The method I have used is similar to the X-Y lissajous, but I use A, B ch, with B ch trig on a 100+MHz o-scope. Show both traces then adjust A freq source to stop the trace walking, decrease the sweep time down to the nsec. range, adjusting the A freq source for minimum trace walk. The faster sweep time gives you more resolution and allows you to adjust 10 MHz to within .001 Hz. Wait 10-30min. and recheck for A trace movement from the B triggered trace. I have achieved <1E-13 MHz separation from the 10 MHz reference source, using this method.
Don Bitters
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Re: Semiconductor test set advice
Hello,
Tek 577 plus Stinkely Consumer Edition 577.
(around 1 grand, probably 400 bux or so)
Tek 577 plus Stinkely 577.
(around 1 grand, probably 1k2 bux or so)
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
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On 2020. 04. 27. 4:47, Dave McGuire wrote: On 4/26/20 10:02 PM, Reginald Beardsley via groups.io wrote:
I'd like to get a semiconductor test set. Preferably something that will send output to a printer. rather than have to photograph a screen. I've got a Peak Atlas DCA75, but I'd like something better. Building one is appealing, but time consuming.
McGuire commented on an HP unit he uses, but I can't find the post and my email to him apparently wound up in the spam bin. Uhh, check your own spam bin, Sparky. ;) I replied to that email,
4/24 12:05AM.
-Dave
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Re: [hp70k] msib sniffer/injector interest query
JF, Thank you for sending the documents.
I have uploaded them here:
The interface specification?indicates that a module-based sniffer will be able to see all traffic between modules within a chassis. Traffic within a module is *not* sent over the external MSIB connectors unless it is destined (or from) a remote chassis, which significantly?reduces?the utility of an external sniffer.
Here's some more thoughts on using a 70100A as the starting point:
This above photo shows the analog board of the 70100A. This board can be removed, and a new PCB can be attached to the standoffs along the top of the module. The digital board can be left in to handle power conversion, with power being provided to the new PCB by the existing ribbon cable from the digital board.
The MSIB connector can be disconnected from the digital board, and reconnected to the new PCB. Here's a closeup:
The RFI ferrite and the MSIB connector can easily be detached and re-routed to the new PCB on the other side of the module.
If we use a Raspberry Pi zero, a USB to Ethernet adapter can be used to provide Ethernet connectivity to the front (or rear) panel. Since the MSIB connector also includes GPIB pins, it makes sense to break those out so that a USB to GPIB adapter can also be included if desired.
The PCB would thus contain the MSIB connector, glue logic to the Raspberry Pi Zero GPIO connector, a power connector, and a connector to connect to the front panel LEDs.
Any thoughts on this general approach?
Does anyone have.a CLIP for the 70100A?
Thanks,
David Slik VE7FIM
On Fri, Apr 24, 2020 at 10:08 PM David & Laura via <davidandlaura= [email protected]> wrote: JF,
Working from the MMS specification documents will accelerate this effort significantly. Can you upload the documents to the list? (or e-mail them directly and I'll upload them for you)
Thanks
David Slik VE7FIM Sorry but it is an unnecessary work : everything you look at is in the MMS_system_specs as the MMS was an open system like Tek TM500/5000 and a lot of companies (Comstron --very impressive ultrafast 4 slots synthesyzer--, Tern Technologies...) built modules for the MMS. I have most of the documents about the system and I sent all in 2014 to a guy Stewart Cobb, asking just for a feedback and prototype. No hear from him... Part of the mails with SC JF, Another interesting idea. It would actually be fairly easy to build a USB-to-MSIB interface box. The external bus is not clocked, it's done with handshaking, so any processor could implement the protocol with bit-banging. You'd need two 37-pin connectors, a bunch of RS-422 driver chips, and a microcontroller with USB. For speed, you'd want USB 2.0. There are plenty of ARM M3 microcontrollers with USB. The hardware would not be hard. Microcontroller software might be harder. The PC display end would be all software, but a lot of it. I wonder how many people would want something like that? Enough to help program it? Enough to buy one? Cheers! --Stu On Dec 17, 2014 8:30 AM, "JF PICARD" < jfphp@...> wrote: Stu Your idea about the CPLD for the bus is very interesting : bus transfers in the MMS system is governed by custom IC in the mainframe et in the plug ins, no longer supplied, and I have allready got the idea to replace these by CPLD, just an idea for me because I have no knowledge in this domain and I found nobody interested by such a project. There is perhaps a small market to offer substitute for this very special ICs. There is another very interesting subjet you will get in touch with your work : the MMS control by a PC . HP offered the 70207A/B (with various options depending of the bundled softwares and accessories : HPBasic, HPIB board...) allowing the total control of any MMS system from a PC running Windows NT. It uses an MSIB interface and a dedicated software. I am hunting it since years without any success, neither in parts nor in software... It could be a side result of your project. 73. JF On Friday, April 24, 2020, 06:27:20 AM GMT+2, Dave McGuire < mcguire@...> wrote:
? I for one think that's a fantastic idea.? I'm a heavy user of MSIB
stuff, and would love to see it extended a bit.
? ? ? ? ? ? -Dave
On 4/23/20 3:59 PM, Jan de Jongh wrote:
> Dear all,
>
> While building my 3rd hp70k-mms system, I want to assess the interest in
> a project idea I've had for the past two years or so: A
> *sniffer/injector* for the hp70k module-interconnection protocol
> (*msib*). All (hardware/software) open source; this is not a commercial
> proposal (apart from e.g. cost-price PCB delivery).
>
> The very rough basic idea is to take a single-width hp70k module
> (likely, for-parts-only), strip everything inside apart from the msib
> interface and mechanical interfaces, and put inside one or more PCBs that:
>
>? * Interface with the msib bus such that 'basic bus transactions' can
>? ? be captured;
>? * Store these 'transactions' into (e.g.) a pcap file on an ssd
>? ? connected to a (say) an embedded Raspberry Pi;
>? * Transfer these 'transactions' over 1 Gbps Ethernet (copper/Fiber
>? ? Optic) from the Raspberry Pi;
>? * Interface over Ethernet both from the front and the rear;
>? * Import the pcap 'transaction' into Wireshark (on a remote machine);
>? * Interpret the 'transactions' using an hp70k-msib dissector;
>? * Perhaps add power monitoring, etc.;
>? * ...
>
>
> This would be the basic first-order requirements of the project. In
> subsequent phases, injection of messages/transactions on the bus and
> running HP calibration (HP-BASIC) software from virtualized containers
> could be implemented.
>
> *My questions:*
>
>? * Is any project already working on something like this that I can
>? ? join (I could not find any)?
>? * Would this be interesting enough to the amateur hp70k community? Is
>? ? there sufficient added value to a tool like this over merely
>? ? swapping modules in order to get things to work?
>? * Does a tool like this have the potential to increase the public
>? ? knowledge on the hp70k mms? Could it reveal calibration data? Is it
>? ? worth it?
>? * *Would anyone be willing to help?* I figure that even a first
>? ? attempt at a working prototype would take over a year, but various
>? ? components of the project (like the pcap format definition,
>? ? wireshark dissectors, web-based interfacing, RPi firmware, KiCAD PCB
>? ? design of bus interfacing, ...) could be isolated and
>? ? designed/implemented in a team-effort... Needless to say this
>? ? project would required >=4 committed enthusiast aficionados...
>
>
> Thanks in advance for your thoughts/vision on this, BR,
> Jan - pa3gyf
>
--
Dave McGuire, AK4HZ
New Kensington, PA
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Re: How to check the accuracy of an HP 5342A frequency counter
I should add that the Rb would have to be assumed working properly - if it's a used, questionable one, then you need to make sure it's OK, evidenced, by a "lock" indication a while after powering up - typically a half hour or less. I see upon reading the thread again, that you apparently see similar (but not identical) frequency readings from three different instruments. They read? slightly differently from each other due to their own references, but since they are much closer to each other than the apparent 170 Hz or so difference from the Rb, I'd vote with the others, that there may be something wrong with it. Be sure to look for that lock indication.
Ed
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Re: How to check the accuracy of an HP 5342A frequency counter
The simple answer is that none of the units are right, and all of them are just fine. You need to study up in the manuals on how the instruments work, what the reference frequencies do, the difference between internal and external references, and how things should be hooked up for various situations.
If you want everything to read the same, choose any one of the available 10 MHz sources (each counter and the SA likely has a 10 MHz ref input and output on the back, and means to select what it's doing), and connect it to all the external reference inputs and signal inputs on every piece of gear. You can buffer it with the amplifier/splitter, or just tee it all together - it will probably work OK this way at 10 MHz. Then think about what's going on.
The Rb unit is probably the closest to exactly "right" in frequency, of all these pieces. You may find that the its apparent sine distortion is from not being terminated in 50 ohms, if you just look with a scope. Each independent reference source is slightly different in frequency with respect to the others, but when you use only one for all the references and signal inputs, they all should read the same. The absolute accuracy is a different story.
Ed
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Re: How to check the accuracy of an HP 5342A frequency counter
Since the SA and the two counters are not primary standards, someone down the line has adjusted them.? They all agree with one another but I'd vote for trusting the standard.? Align the counters and the SA to the standard.
Unlikely that you could set an OCXO 170 Hz out.
The OCXO in my 8566B was 76 Hz out compared to my Trimble GPSDO.? The closest I could get it was 70 Hz out.? I found a NOS OCXO and it was within 0.1 Hz after running for a couple of weeks. ?(The bad OCXO has since died after running it outside the SA.? No 10 MHz at all now.)
I'd guess the FE-5680A isn't locked.? They do sit low, then every minute or so, sweep upwards looking for lock.? I'd put the FE-5680A on the SA and watch it from cold.? See if it locks.
Orin.
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Re: How to check the accuracy of an HP 5342A frequency counter
One suggestion.? Compare to WWV and you will get your answer immediately.
Bob
On Sunday, April 26, 2020, 08:37:34 PM PDT, Bob Albert via groups.io <bob91343@...> wrote:
Since the SA and the two counters are not primary standards, someone down the line has adjusted them.? They all agree with one another but I'd vote for trusting the standard.? Align the counters and the SA to the standard.
If you can find a way to verify the standard, do that.? But a gross error is unlikely from it.
Bob
...whoops hit reply too quick! To continue, the frequency reference appears like it needs to be checked. Bob's suggestion of using your o-scope in X-Y mode is a good place to start.
Sean
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Re: How to check the accuracy of an HP 5342A frequency counter
Since the SA and the two counters are not primary standards, someone down the line has adjusted them.? They all agree with one another but I'd vote for trusting the standard.? Align the counters and the SA to the standard.
If you can find a way to verify the standard, do that.? But a gross error is unlikely from it.
Bob
...whoops hit reply too quick! To continue, the frequency reference appears like it needs to be checked. Bob's suggestion of using your o-scope in X-Y mode is a good place to start.
Sean
|
Re: How to check the accuracy of an HP 5342A frequency counter
...whoops hit reply too quick! To continue, the frequency reference appears like it needs to be checked. Bob's suggestion of using your o-scope in X-Y mode is a good place to start.
Sean
|
Sam Reaves