Re: Testing dummy loads with a VNA
On Sat, Mar 7, 2020 at 01:52 PM, Jinxie wrote:
dummy load is a termination with only an input!
If its a parallel connection, yes. Why not a series connection? VNAs are intended to do "thru' measurments on systems of a characteristic impedaance (probably 50 ohms) Some are able to do "single port' i.e. connect the load across the TX port and read that. Thats not actually a 'network analysis' because a dummy load is not exactly a network (read about Fosters networks). Why cant you connect the dummy load in series between the TX and another input? (other than the obvious mechanical constraints.) That would test the resistive element by itself. Then test the rest without the load. Could reveal some interesting information such as "oh, the stray reactance is in the fixture, not the resistive load" A good RF generator would work as well... read it with a scope.
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693B sweep oscillator restoration
Hi all,
I came across a 693B sweep oscillator that's in pretty nice shape considering it's age. It seems to be fully functional, tunes accurately, etc. Front panel mechanicals seem to be in good order. ALC seems wonky, though the the sweep is fairly flat across the 4-8 MC range that it covers. I'd like to clean it up and get it running as it did when it was new if possible.
1) I can't seem to find any manuals for this series of sweep oscillators. Am I just looking in the wrong place? Artek has 69xD series manuals, but not B. Not sure what the differences are.
2) What's the best way to get all the dust out?
3) Any particular electrical pitfalls? It is a piece of vacuum tube test equipment so naturally there are dangerous voltages present. Also large H fields from the BWT oscillator.
Thanks!
Sean
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Re: Testing dummy loads with a VNA
On March 7, 2020 5:15:49 PM "Jinxie" <paul666@...> wrote: It's an HP 8754A. And I have a suitable phase-matched splitter (one in, three out). I was under the impression S parameter test sets were only needed for testing active devices under power. This is totally passive (obviously). S-parameter test sets don't have anything to do with active vs. passive. First thing's first, please read up on S ("scattering") parameters a bit, as I'm typing on my phone and explaining it would be painful in this environment. The essence of it is it turns your source, R, A, and B ports into two ports, 1 and 2, with appropriate switching and directional couplers (or bridges) to look at transmission from port 1 to port 2 (S21) transmission from port 2 to port 1(S12), reflection of energy coming from port 1 back into port 1 (S11), and the same for port 2 (S22). For a dummy load (or "terminator") you want to measure S11. This is one of the big basic things that VNAs are built to do. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Testing dummy loads with a VNA
It's an HP 8754A. And I have a suitable phase-matched splitter (one in, three out). I was under the impression S parameter test sets were only needed for testing active devices under power. This is totally passive (obviously).
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Re: Testing dummy loads with a VNA
On March 7, 2020 5:08:22 PM "Dave McGuire" <mcguire@...> wrote: On March 7, 2020 5:03:48 PM "Jinxie" <paul666@...> wrote:
I don't have a "port one". I've got one RF out and 3 inputs, R, A & B. That's all. Is this an 8505A? 8753?
You need either a good splitter or (better) an S-parameter test set. THEN connect to port one. :) Ack, sorry a directional coupler. But best to find an appropriate S-parameter test set for your VNA. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Testing dummy loads with a VNA
On March 7, 2020 5:03:48 PM "Jinxie" <paul666@...> wrote: I don't have a "port one". I've got one RF out and 3 inputs, R, A & B. That's all. Is this an 8505A? 8753? You need either a good splitter or (better) an S-parameter test set. THEN connect to port one. :) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Testing dummy loads with a VNA
I don't have a "port one". I've got one RF out and 3 inputs, R, A & B. That's all.
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Re: Testing dummy loads with a VNA
On March 7, 2020 4:52:47 PM "Jinxie" <paul666@...> wrote: I can't find any info on how to connect a VNA for testing dummy loads. All the set-ups I'm seeing are for thru-line measurements for DUTs like filters which of course have input and output ports. I'm not seeing any suggested set-ups where the dummy load is a termination with only an input! Is that too much to ask??
So I'd like to characterize various 50 ohm dummy loads I have using polar plots. I know how to set the controls for the bandwidth and whatnot I want to see; it's just hooking up the DUT I'm struggling with; which cables go where and is a 'tee' needed? Can some kind soul assist, please? It's simplicity in itself: just connect it to port one, and measure S11. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Testing dummy loads with a VNA
Hi all,
I can't find any info on how to connect a VNA for testing dummy loads. All the set-ups I'm seeing are for thru-line measurements for DUTs like filters which of course have input and output ports. I'm not seeing any suggested set-ups where the dummy load is a termination with only an input! Is that too much to ask??
So I'd like to characterize various 50 ohm dummy loads I have using polar plots. I know how to set the controls for the bandwidth and whatnot I want to see; it's just hooking up the DUT I'm struggling with; which cables go where and is a 'tee' needed? Can some kind soul assist, please?
THanks!
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Re: Q: Future Plus PCI-X probeable adapter for HP/Agilent 16700/16900 logic analyzers
Kuba,
Thanks for sharing this method for reverse engineering. Pretty cool idea!
Keith
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Show quoted text
On 3/7/2020 11:25 AM, Kuba Ober wrote: An alternative these days is to run the debugged OS in a virtual machine, and sniff the transactions as they pass between the guest system and the emulated hardware, or even between the guest system and a ¡°half¡± pass-through real hardware (pass through with intercepts). This is doable in reasonable time eg in KVM as it¡¯s open source; you need to stick some logging into the path that deals with pass through or into the emulated usb host. I¡¯ve done that to run our client software as a black box that talked to an emulated USB device that was ¡°connected¡± to the microcontroller emulator that ran the firmware of the actual device. It was great for automated tests. Might look good on someone¡¯s resume: ¡°set up a dev-ops system for firmware development¡± :)
Cheers, Kuba
7 mars 2020 kl. 2:06 fm skrev Glen Slick <glen.slick@...>:
?On Fri, Mar 6, 2020 at 9:38 AM Tony Jones <tony@...> wrote:
Anyone know much about these? Allows you to connect a 16700/16900 to a PCI card.
I picked up three of them with a used system and was able to get the manual and software from the manufacturer but havn't tried them yet.
I used a FuturePlus FS2000 PCI Analysis Probe with a 16500C and 16700A
many years ago for debugging USB host controller driver issues and
needed to see what transactions were occurring on the bus. Only needed
to use it a few times, but when I did there wasn't really anything
else that would have done the job. I still have one or two FS2000
probe cards.
They are obsolete for the most part now that almost everything current
uses PCI Express, although some people here still work with obsolete
technology.
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Re: Q: Future Plus PCI-X probeable adapter for HP/Agilent 16700/16900 logic analyzers
An alternative these days is to run the debugged OS in a virtual machine, and sniff the transactions as they pass between the guest system and the emulated hardware, or even between the guest system and a ¡°half¡± pass-through real hardware (pass through with intercepts). This is doable in reasonable time eg in KVM as it¡¯s open source; you need to stick some logging into the path that deals with pass through or into the emulated usb host. I¡¯ve done that to run our client software as a black box that talked to an emulated USB device that was ¡°connected¡± to the microcontroller emulator that ran the firmware of the actual device. It was great for automated tests. Might look good on someone¡¯s resume: ¡°set up a dev-ops system for firmware development¡± :)
Cheers, Kuba
toggle quoted message
Show quoted text
7 mars 2020 kl. 2:06 fm skrev Glen Slick <glen.slick@...>:
?On Fri, Mar 6, 2020 at 9:38 AM Tony Jones <tony@...> wrote:
Anyone know much about these? Allows you to connect a 16700/16900 to a PCI card.
I picked up three of them with a used system and was able to get the manual and software from the manufacturer but havn't tried them yet.
I used a FuturePlus FS2000 PCI Analysis Probe with a 16500C and 16700A
many years ago for debugging USB host controller driver issues and
needed to see what transactions were occurring on the bus. Only needed
to use it a few times, but when I did there wasn't really anything
else that would have done the job. I still have one or two FS2000
probe cards.
They are obsolete for the most part now that almost everything current
uses PCI Express, although some people here still work with obsolete
technology.
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Re: CRT needed for HP 8505A
Hi if? the picture shows all the packing
then the packing was not correct
?
I now take pictures before opening a
package and then use them for the clam?
The big problem is people selling items on
Ebay? that have zero technical brain power
Last item was a vintage whetstone bridge just
with a bit of bubble rap later realised the person usually sells baby soft toys
and clothes
?
If it was well packed Have you asked the shipping
company to replace it
?
That might sharpen them up ?the EBAY
shippers keep leaving things on the front door step and signings for them, them
selves
?
Best regards Paul
?
?
?
Hello together,
Thanks for the Information, but I guess I was a little to late for that:
On Sat, Feb 15, 2020 at 11:58 PM, Sam Reaves wrote:
Did you see where Jeff Kruth has a CRT available for your HP8505A? He
posted a message on this in the last few days.
Maybe slow boat to Europe or if you know
someone that is visiting in the states can pick it up and carry it back for you
as baggage (well packed of course).
Sam
W3OHM
And bought another one. unfortunately that one arrived like that:
I guess the metal shielding was the problem during transport. Therefore I am
still looking for a replacement...
Regards,
Gerrit
No virus found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.
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Re: Advice on Accessories for HP Equipment
Hi,
The 8590xE should have? reference input. It is next to the fan on the rear panel and is conected to the reference output by a solid bar type BNC to BNC link.
1PPM frequency meaurement could be a challenge for a 859xE depending on the actual signal frequeny, span and resolution bandwidth. The GPSDO performance is likely to be orders of magnitude better than the other errors.
Robert G8RPI.
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Re: Advice on Accessories for HP Equipment
I'd like to suggest getting one of Leo Bodnar's excellent GPSDOs. I have the 2 output version which I needed to run an SDRplay RSP2 and a VNWA 3E. I bought the outside mount antenna kit from Leo at the same time. Works a treat.
I've been making my own H field probes from solid shield RG402 and can't really imagine why one would buy one at the prices charged. All they are is a wire loop which is shielded so it only responds to the magnetic field.
Reg
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Re: CRT needed for HP 8505A
Hello together,
Thanks for the Information, but I guess I was a little to late for that:
toggle quoted message
Show quoted text
On Sat, Feb 15, 2020 at 11:58 PM, Sam Reaves wrote:
Did you see where Jeff Kruth has a CRT available for your HP8505A? He posted a message on this in the last few days.
Maybe slow boat to Europe or if you know someone that is visiting in the states can pick it up and carry it back for you as baggage (well packed of course).
Sam
W3OHM
And bought another one. unfortunately that one arrived like that:  I guess the metal shielding was the problem during transport. Therefore I am still looking for a replacement... Regards, Gerrit
|
Re: Q: Future Plus PCI-X probeable adapter for HP/Agilent 16700/16900 logic analyzers
On Fri, Mar 6, 2020 at 9:38 AM Tony Jones <tony@...> wrote:
Anyone know much about these? Allows you to connect a 16700/16900 to a PCI card.
I picked up three of them with a used system and was able to get the manual and software from the manufacturer but havn't tried them yet.
I used a FuturePlus FS2000 PCI Analysis Probe with a 16500C and 16700A many years ago for debugging USB host controller driver issues and needed to see what transactions were occurring on the bus. Only needed to use it a few times, but when I did there wasn't really anything else that would have done the job. I still have one or two FS2000 probe cards. They are obsolete for the most part now that almost everything current uses PCI Express, although some people here still work with obsolete technology.
|
Re: Advice on Accessories for HP Equipment
An ovenized XTAL based or PLL unit at 10Mc should be easy to find. Just Google it. I dont know if any of the new AWGs can hold 1ppm or not.
As to testing, my first suggestion that a proper room is the first point... cant do high precision noise detection in a noisy lab environment
It sounds as if youll be sniffing down around -150dB...SWAG... may need a heavily shielded a/o anechoic room as they sometimes use for microwave testing. Filtered power lines, DC lights,,,
ESD control. Maybe even underground depending on how sensitive it is.
We are all neophytes when challenging the unknown. If not, it wouldnt be unknown!
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Re: Advice on Accessories for HP Equipment
Cheap NFP are typically not calibrated or accurate.? I might have an extra hp NFP system that I could spare¡ and it is in cal.?
Locking to? a gps would yield decent accuracy usually unless you are way up in the new range¡ then it would be a bit higher then your required ppm.?
Pete wa2odo?
On Fri, Mar 6, 2020, 4:32 PM Steve Hendrix < SteveHx@...> wrote: I have two needs for upcoming projects, at most loosely related to
one another. The total knowledge of this group makes me look like a
complete neophyte, with only a few decades of experience, so maybe
you can guide me away from making a mistake.
The first need is for a frequency reference. I have a project in
progress now, where within a couple weeks I'm going to need to be
able to measure frequency to better than 1 ppm. I'm thinking to use a
GPSDO to feed a reference into my HP8595E and check its calibration
(it doesn't seem to have an external reference input), or to feed it
into the Ext Ref input of my HP8714ET. I see a lot of different GPSDO
units on ePay; is there anything I should look for or avoid? Note
that my office / lab is rather marginal for receiving GPS, with a
couple floors above it as well as a lot of trees. But I could if
necessary put the GPSDO outdoors and feed the 10 MHz inside on a cable.
The second need is a near field probe and/or calibrated antenna for
doing pre-compliance measurements on designs that usually come in so
far below the limits as to be hard to even detect. I see about three
different classes of NFP on ePay: a grouping around $30, another
around $100, and yet another around $500, all for kits of four NFP.
What are the differences, and again what should I watch for?
Any hints welcome, and if I'm too far OT just say so.
Steve Hendrix
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Advice on Accessories for HP Equipment
I have two needs for upcoming projects, at most loosely related to one another. The total knowledge of this group makes me look like a complete neophyte, with only a few decades of experience, so maybe you can guide me away from making a mistake.
The first need is for a frequency reference. I have a project in progress now, where within a couple weeks I'm going to need to be able to measure frequency to better than 1 ppm. I'm thinking to use a GPSDO to feed a reference into my HP8595E and check its calibration (it doesn't seem to have an external reference input), or to feed it into the Ext Ref input of my HP8714ET. I see a lot of different GPSDO units on ePay; is there anything I should look for or avoid? Note that my office / lab is rather marginal for receiving GPS, with a couple floors above it as well as a lot of trees. But I could if necessary put the GPSDO outdoors and feed the 10 MHz inside on a cable.
The second need is a near field probe and/or calibrated antenna for doing pre-compliance measurements on designs that usually come in so far below the limits as to be hard to even detect. I see about three different classes of NFP on ePay: a grouping around $30, another around $100, and yet another around $500, all for kits of four NFP. What are the differences, and again what should I watch for?
Any hints welcome, and if I'm too far OT just say so.
Steve Hendrix
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Re: HP 651B Oscillator restoration and an OOPS!!
Aren't these children a bit excessive - maybe we should block both of them.
Cummon guys - GROW UP
Quoting "Dale H. Cook" <bridgewaterma@...>:
toggle quoted message
Show quoted text
On 3/6/2020 12:46 PM, David Campbell wrote:
... they were that badly oxidised That sounds like the parts were long stored in a very poor environment. I have never seen that in the original caps in any of my 16 HP instruments of that vintage (13 working and 3 parts junkers). Mine, however, were almost all purchased from individuals whom I know, or at meets, and in all of those cases I was able to have a look inside to evaluate condition. It is common for the HP caps of that vintage to look somewhat poor due to deterioration of the plastic sleeves but to measure fine at rated voltage for both C and D on a GR bridge.
--
Dale H. Cook, Member, NEHGS, AGS, MA Soc. of Mayflower Descendants;
Plymouth Co. MA Coordinator for the USGenWeb Project
Administrator of
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Dave McGuire
Jinxie
Keith Monahan
Paul Bicknell
