Re: Peak vs. Average Power Sensors
Thanks, Kuba. The idea about synchronous sampling being required near the limit is new to me, so I'm off to do some research.
I think you answered my question, and this limitation won't affect me in practice. My question was really whether I could use the 20k sampling rate to pick up peak power in an AM (actually, SSB) transmission that has about 3.5 kHz bandwidth. With a 20k sampling rate, that shouldn't be a problem.
Thanks,
John
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On 10/30/18 4:27 PM, Kuba Ober wrote: That’s correct as far as amplitude modulations go, and also the sampling close to the Nyquist limit only works when it’s synchronous with the input signal: the Nyquist limit isn’t some general “sampling works up to here” frequency. Without synchronous sampling, there will be large amplitude errors, getting lower in frequency as the signal approaches the limit. If you, say, modulate at 4.9kHz, and sample at 10kHz, the envelope itself will have a secondary envelope at 100Hz, and only its peaks will have the correct amplitude:
image1.png
Cheers, Kuba
30 okt. 2018 kl. 15:59 skrev John Ackermann N8UR <jra@... <mailto:jra@...>>:
I'm trying to educate myself about the newer USB power sensors. ?When I look for example at the U2043XA (average) and U2044XA (peak and average) specs, I see that both can do at least 20K measurements/second. ?The 2044XA has a video bandwidth of 5 MHz, while that's not specified for the 2043XA.
My question is whether the averaging sensor can still provide a peak reading, if the modulation is slow enough.
If I can make 20K measurements per second, it seems I should be able to follow a modulation envelope of up to 10 kHz (Nyquist sampling) and use the computer to process that data stream to catch and report the peak level over some time period. ?In fact, in theory I could process all the samples to fully reconstruct the modulation.
Is that correct, or am I missing something?
Thanks,
John
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Re: HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
It may be obvious, but you are using single density (720k) disks? The HD (1.44Mb) ones won't write in the old drives (They may read if written to in a 1.44Mb drive in 720k format).
Older floppy models with all the control signals tend to fetch premium prices?on ebay as some industrial equipment e.g. CNC machines used them and the machine is still valuable.
Robert G8RPI.
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Re: HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
Hello Paul,
Thank you so much for the detailed information.
Yes, I see that the C model drive has a single ribbon cable connector, while the D model drive has a separate power connector (and square eject buttons as you suggest). I hadn't tried the alternate formatting (256 byte sectors) yet. I agree disassembly is in the offing - on the D model the right-hand drive does not latch the diskette into position. I wasn't aware of the differing rotational speed (!!! :-( )
The panasonic drive you mention seems to be available enough on ebay and similar sites, so that may be a starting point.
I'll study the manual (I did download successfully) and see whether a I can gather enough resource to make the attempt worthwhile (I'll probably have other questions). As for the interposer board, that would be easy to cobble up as a PC board (I do many of my own small circuit boards) and I'd be glad to share the results if that would be useful.
Thanks again!
Dave
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Re: HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
Further to my previous comments the two drive I modified to work on a 9122C are a Panasonic JU-257A606P and a YE Data YD-702D-6037D.? One thing you may encounter there are later versions of both of these drives that have less configuration options and will not be suitable.? On the YE Data drive I had to put a wire jumper on the board to get all the signals out that are required, I believe I may have had to do that with the Panasonic drive as well.? I happened to have several 1.44 diskette drives handy to experiment with.? You will probably have better luck with older drives, it seems a lot of the more recent ones are tailored for PC and have little in the way on configuration options.? The HP drives also have the power integrated into the signal cable so I made up a little interposer to go between the cable and the drive to break out the power and also to remap some of the pins.
The service guide for the 9122C can be found at and it contains a pinout of the drive cable connector which can help guide you to adapting a drive.
While I know nothing about the instrument you are trying to connect to, it may be that it is trying to format the diskettes at 256 bytes / sector and if the diskettes have been formatted differently before it may take a few tries before it is successful, bulk erasing the diskette first can be helpful for this.
Paul.
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On 2018-10-30 7:52 PM, Paul Berger wrote: With a little work certain 1.44 drives can be made to work in a 9122C the usual stumbling block is the controller in the 9122 wants to see the ready signal, but I did manage to make a couple drives work, but don't have the models handy.
The 9122D is a different story, it uses 720K drives that turn at 600 RPM and unlike most other 3.5 diskette drives.? There where two versions of drives used. The earlier models used a full high drive with a square eject button on the bottom right of the drive, about the only place you can get replacements for this drive is from other 9122S/D units or there where also a couple disk/ diskette combo units that used these drives.? The newer version is a half high drive with a rectangular eject button at the bottom right, this drive was used in a lot of HP equipment so replacements are easier to find.? One of the prevalent problems with these drives and especially the full high versions is lubricants used on the load/eject mechanism dry and becomes gummy and the diskettes do not load or eject properly and it is dangerous because the upper head may not retract properly and if you pull out the diskette when it is like this the upper head will come out with it.? I would strongly recommend you open the units and do a general inspect, clean and lube.
Paul.
On 2018-10-30 7:39 PM, David Feldman via Groups.Io wrote:
I ended up with both HP 9122C and 9122D (dual floppy drive) units. Both are recognized by my 8753 network analyzer (up to the point that setting incorrect GPIB address and setting incorrect disc/volume number has the expected error message results), all four drives make familiar sounds during power-up and normal operation, however, only one of the drives (in the 9122C) can read a diskette (list files on the media), and none can write or initialize diskettes. I am uncertain whether the onboard controllers are fully functional, but both appear complete and physically undamaged.
My question is this - can a contemporary (i.e., a 3-1/2" 1.4MB floppy drive) be adapted for use in either of these units? The 9122C uses a single (0.05" pitch) ribbon cable between the drives and the controller board; the 9122D has a somewhat narrower (0.05" pitch) ribbon cable and a 4-pin power connector. None of the connectors are identical to those used in contemporary floppy drives. I haven't looked for/at service documentation (yet). My last exposure to floppy drive equipment (at engineering, hardware and firmware level) was in the mid-late 1970s (!), so I'd not be adverse to a modest engineering project if there's a sign that this sort of thing has been successfully attempted in the past.
My other question - do you happen to have any drives (of either type) you'd be willing to part with?
Thanks,
Dave
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Re: HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
I have the combo floppy and hard drive. Worked fine with my 8753D last I checked. It is heavy though where are you located? send reply directly if you can mycall@...
73 Eugene W2HX
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of David Feldman via Groups.Io Sent: Tuesday, October 30, 2018 6:39 PM To: [email protected]Subject: [HP-Agilent-Keysight-equipment] HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive? I ended up with both HP 9122C and 9122D (dual floppy drive) units. Both are recognized by my 8753 network analyzer (up to the point that setting incorrect GPIB address and setting incorrect disc/volume number has the expected error message results), all four drives make familiar sounds during power-up and normal operation, however, only one of the drives (in the 9122C) can read a diskette (list files on the media), and none can write or initialize diskettes. I am uncertain whether the onboard controllers are fully functional, but both appear complete and physically undamaged. My question is this - can a contemporary (i.e., a 3-1/2" 1.4MB floppy drive) be adapted for use in either of these units? The 9122C uses a single (0.05" pitch) ribbon cable between the drives and the controller board; the 9122D has a somewhat narrower (0.05" pitch) ribbon cable and a 4-pin power connector. None of the connectors are identical to those used in contemporary floppy drives. I haven't looked for/at service documentation (yet). My last exposure to floppy drive equipment (at engineering, hardware and firmware level) was in the mid-late 1970s (!), so I'd not be adverse to a modest engineering project if there's a sign that this sort of thing has been successfully attempted in the past. My other question - do you happen to have any drives (of either type) you'd be willing to part with? Thanks, Dave
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Re: HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
With a little work certain 1.44 drives can be made to work in a 9122C the usual stumbling block is the controller in the 9122 wants to see the ready signal, but I did manage to make a couple drives work, but don't have the models handy.
The 9122D is a different story, it uses 720K drives that turn at 600 RPM and unlike most other 3.5 diskette drives.? There where two versions of drives used. The earlier models used a full high drive with a square eject button on the bottom right of the drive, about the only place you can get replacements for this drive is from other 9122S/D units or there where also a couple disk/ diskette combo units that used these drives.? The newer version is a half high drive with a rectangular eject button at the bottom right, this drive was used in a lot of HP equipment so replacements are easier to find.? One of the prevalent problems with these drives and especially the full high versions is lubricants used on the load/eject mechanism dry and becomes gummy and the diskettes do not load or eject properly and it is dangerous because the upper head may not retract properly and if you pull out the diskette when it is like this the upper head will come out with it.? I would strongly recommend you open the units and do a general inspect, clean and lube.
Paul.
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On 2018-10-30 7:39 PM, David Feldman via Groups.Io wrote: I ended up with both HP 9122C and 9122D (dual floppy drive) units. Both are recognized by my 8753 network analyzer (up to the point that setting incorrect GPIB address and setting incorrect disc/volume number has the expected error message results), all four drives make familiar sounds during power-up and normal operation, however, only one of the drives (in the 9122C) can read a diskette (list files on the media), and none can write or initialize diskettes. I am uncertain whether the onboard controllers are fully functional, but both appear complete and physically undamaged.
My question is this - can a contemporary (i.e., a 3-1/2" 1.4MB floppy drive) be adapted for use in either of these units? The 9122C uses a single (0.05" pitch) ribbon cable between the drives and the controller board; the 9122D has a somewhat narrower (0.05" pitch) ribbon cable and a 4-pin power connector. None of the connectors are identical to those used in contemporary floppy drives. I haven't looked for/at service documentation (yet). My last exposure to floppy drive equipment (at engineering, hardware and firmware level) was in the mid-late 1970s (!), so I'd not be adverse to a modest engineering project if there's a sign that this sort of thing has been successfully attempted in the past.
My other question - do you happen to have any drives (of either type) you'd be willing to part with?
Thanks,
Dave
|
HP 9122C & 9122D floppy drive units - adapt to use a contemporary (3.5" 1.4MB) diskette drive?
I ended up with both HP 9122C and 9122D (dual floppy drive) units. Both are recognized by my 8753 network analyzer (up to the point that setting incorrect GPIB address and setting incorrect disc/volume number has the expected error message results), all four drives make familiar sounds during power-up and normal operation, however, only one of the drives (in the 9122C) can read a diskette (list files on the media), and none can write or initialize diskettes. I am uncertain whether the onboard controllers are fully functional, but both appear complete and physically undamaged.
My question is this - can a contemporary (i.e., a 3-1/2" 1.4MB floppy drive) be adapted for use in either of these units? The 9122C uses a single (0.05" pitch) ribbon cable between the drives and the controller board; the 9122D has a somewhat narrower (0.05" pitch) ribbon cable and a 4-pin power connector. None of the connectors are identical to those used in contemporary floppy drives. I haven't looked for/at service documentation (yet). My last exposure to floppy drive equipment (at engineering, hardware and firmware level) was in the mid-late 1970s (!), so I'd not be adverse to a modest engineering project if there's a sign that this sort of thing has been successfully attempted in the past.
My other question - do you happen to have any drives (of either type) you'd be willing to part with?
Thanks,
Dave
|
Re: Peak vs. Average Power Sensors
That’s correct as far as amplitude modulations go, and also the sampling close to the Nyquist limit only works when it’s synchronous with the input signal: the Nyquist limit isn’t some general “sampling works up to here” frequency. Without synchronous
sampling, there will be large amplitude errors, getting lower in frequency as the signal approaches the limit. If you, say, modulate at 4.9kHz, and sample at 10kHz, the envelope itself will have a secondary envelope at 100Hz, and only its peaks will have the
correct amplitude:
Cheers, Kuba
30 okt. 2018 kl. 15:59 skrev John Ackermann N8UR < jra@...>:
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I'm trying to educate myself about the newer USB power sensors. ?When I look for example at the U2043XA (average) and U2044XA (peak and average) specs, I see that both can do at least 20K measurements/second. ?The 2044XA has a video bandwidth
of 5 MHz, while that's not specified for the 2043XA.
My question is whether the averaging sensor can still provide a peak reading, if the modulation is slow enough.
If I can make 20K measurements per second, it seems I should be able to follow a modulation envelope of up to 10 kHz (Nyquist sampling) and use the computer to process that data stream to catch and report the peak level over some time period. ?In fact,
in theory I could process all the samples to fully reconstruct the modulation.
Is that correct, or am I missing something?
Thanks,
John
|
Peak vs. Average Power Sensors
I'm trying to educate myself about the newer USB power sensors. When I look for example at the U2043XA (average) and U2044XA (peak and average) specs, I see that both can do at least 20K measurements/second. The 2044XA has a video bandwidth of 5 MHz, while that's not specified for the 2043XA.
My question is whether the averaging sensor can still provide a peak reading, if the modulation is slow enough.
If I can make 20K measurements per second, it seems I should be able to follow a modulation envelope of up to 10 kHz (Nyquist sampling) and use the computer to process that data stream to catch and report the peak level over some time period. In fact, in theory I could process all the samples to fully reconstruct the modulation.
Is that correct, or am I missing something?
Thanks,
John
|
Re: Transistors for the A17 voltage regulator 8642B
Yes its connected to A5, I notice the very moment I push the power button some of the LED indicators on the regulator blip on.
Also I have a working 8642B with a regulator I can take out and put into the parts 8642B though my concern is not to damage the working parts from the functional 8642B, any thoughts? Perhaps if there is a serious problem that is what fuses are for.
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Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
That was John K Seamon. It is very nice. I have two of them, but sadly, he’s out of them and doesn’t plan to offer them again.?
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On Oct 30, 2018, at 13:37, bownes < bownes@...> wrote:
And a time nut did a beagle bone based replacement for the 6809 board that is quite nice.? On Oct 30, 2018, at 14:35, Glen Hoag < hoag@...> wrote: I have both a 5370A (upgraded by HP to 5370B) and a 5370B at home. I can check, but don’t recall a separate RAM board.?
Early 5370s used a Fairchild F8 family CPU. When the F8 reached end of life, HP redesigned the CPU around the Motorola 6800 or 6809; I don’t remember offhand. IIRC, consolidation of the ROMs onto the CPU board occurred at this time.?
—Glen Hoag
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Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
And a time nut did a beagle bone based replacement for the 6809 board that is quite nice.?
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On Oct 30, 2018, at 14:35, Glen Hoag < hoag@...> wrote: I have both a 5370A (upgraded by HP to 5370B) and a 5370B at home. I can check, but don’t recall a separate RAM board.?
Early 5370s used a Fairchild F8 family CPU. When the F8 reached end of life, HP redesigned the CPU around the Motorola 6800 or 6809; I don’t remember offhand. IIRC, consolidation of the ROMs onto the CPU board occurred at this time.?
—Glen Hoag ? hoag@...There's nothing about A13 in the 5370A manual I have. On Tue, Oct 30, 2018 at 10:19 AM Dr. David Kirkby from Kirkby Microwave Ltd < drkirkby@...> wrote: Only the earlier 5370As used that ROM slot.? The ROM is on the CPU board in later 'A's and 'B's.
Cheers. Do you know anything about the memory expansion board? Is that another left-over from the older A version?
Dave
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
I have both a 5370A (upgraded by HP to 5370B) and a 5370B at home. I can check, but don’t recall a separate RAM board.?
Early 5370s used a Fairchild F8 family CPU. When the F8 reached end of life, HP redesigned the CPU around the Motorola 6800 or 6809; I don’t remember offhand. IIRC, consolidation of the ROMs onto the CPU board occurred at this time.?
—Glen Hoag
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On Oct 30, 2018, at 13:22, Orin Eman < orin.eman@...> wrote: There's nothing about A13 in the 5370A manual I have. On Tue, Oct 30, 2018 at 10:19 AM Dr. David Kirkby from Kirkby Microwave Ltd < drkirkby@...> wrote: Only the earlier 5370As used that ROM slot.? The ROM is on the CPU board in later 'A's and 'B's.
Cheers. Do you know anything about the memory expansion board? Is that another left-over from the older A version?
Dave
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
There's nothing about A13 in the 5370A manual I have.
On Tue, Oct 30, 2018 at 10:19 AM Dr. David Kirkby from Kirkby Microwave Ltd < drkirkby@...> wrote: Only the earlier 5370As used that ROM slot.? The ROM is on the CPU board in later 'A's and 'B's.
Cheers. Do you know anything about the memory expansion board? Is that another left-over from the older A version?
Dave
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
Re: HP8405A - Uncommon component failure?
Silver mica caps suffer from silver migration. They develop leakage, until they short out. They cause a lot of noise problems in older radios, in IF transformers as they arc along the tips of the migrated silver. It is so prevalent that it is named 'Silver Mica Disease' among people who collect old radios.
One TV transmitter I worked on used a large silver mica capacitor that cost over $500 that would die every few years, and often with a loud bang as it took out the power supply to that 4CX250 driver stage.
Michael A. Terrell
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-----Original Message----- From: Scott McGrath <scott@...>
Sent: Oct 30, 2018 10:20 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8405A - Uncommon component failure?
Ive seen those components fail before but usually with those failure tends to be mechanical rather than electrical.
Thermal cycling, mounting stress, defect in bonding leads etc. as they usually fail ‘open’ instead of short.
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Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
Dr. David Kirkby from Kirkby Microwave Ltd
Only the earlier 5370As used that ROM slot.? The ROM is on the CPU board in later 'A's and 'B's.
Cheers. Do you know anything about the memory expansion board? Is that another left-over from the older A version?
Dave
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
Re: 5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
Only the earlier 5370As used that ROM slot.? The ROM is on the CPU board in later 'A's and 'B's.
On Tue, Oct 30, 2018 at 9:48 AM Dr. David Kirkby from Kirkby Microwave Ltd < drkirkby@...> wrote: I have a 5370B which I bought from eBay with supposedly error 02, which is an overflow and user error. However,? on opening it up I can see the problem is more than that, because one of the 7 A fuses in the power supply board has gone, and the -5.2 V supply is not present. The fuse looks like the cap is actually pulled off of it, so maybe its a physical problem rather than the element is blown.
I am going to order a replacement fuse as I have nothing like this, but while I am waiting for it to appear, is anyone aware of any common faults on this? Also, I have 4 sets of edge connectors with no boards in them. 1) XA14 service aid 2) XA13 memory option 3) XA12 ROM 4) XA12 Spare the third one in that list, XA12 ROM, sounds as though it should be present, but I have no idea if that's the case. I do have another 5370B here, so swapping/checking parts is in "theory" easy, but the thing is buried under so much other test equipment that getting it out is no easy task. Dave ? -- Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
5370B problem. -5 V rail not working, and 7 A fuse in -10 V unregulated supply blown.
Dr. David Kirkby from Kirkby Microwave Ltd
I have a 5370B which I bought from eBay with supposedly error 02, which is an overflow and user error. However,? on opening it up I can see the problem is more than that, because one of the 7 A fuses in the power supply board has gone, and the -5.2 V supply is not present. The fuse looks like the cap is actually pulled off of it, so maybe its a physical problem rather than the element is blown.
I am going to order a replacement fuse as I have nothing like this, but while I am waiting for it to appear, is anyone aware of any common faults on this? Also, I have 4 sets of edge connectors with no boards in them. 1) XA14 service aid 2) XA13 memory option 3) XA12 ROM 4) XA12 Spare the third one in that list, XA12 ROM, sounds as though it should be present, but I have no idea if that's the case. I do have another 5370B here, so swapping/checking parts is in "theory" easy, but the thing is buried under so much other test equipment that getting it out is no easy task. Dave ? -- Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
Tel 01621-680100 / +44 1621-680100
|
Re: HP85050A open standard 1250-1873 wanted
But I did test the same DUT by HP8753E and Advantest R3765BH or R3767C . They have the same results.R3765/7 are using Maury Cal. Kit. 從我的 iPhone 傳送 Dr. David Kirkby from Kirkby Microwave Ltd < drkirkby@...> 於 2018年10月30日 22:36 寫道：
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Please On Tue, 30 Oct 2018, 14:05 Yiu On Tony C via Groups.Io, <tonycheung_hk= [email protected]> wrote: Hi members :
Anyone still using HP85050A with 1250-1873? open standard ??
Any photos or extra can offer ??
You might want to consider asking on?
In my 8510A have the cal. standard file A1. when cal. with 85050B can see the actually reading have some error in value measurement value ?
I compare DUT measured with my 8753E VNA .
Any advise ?
The 8753 uses the 85031 (from memory) which is a fairly simple standard with a waveguide beyond cutoff. A fringing capacitance around 82 fF is defined, but that is not very accurate as the fringing capacitance depends on the protrusion of the centre contact which is not well defined. Measure a few APC7 connectors with connector guages from the 85050B. I am unsure if the 85050A has guages.?
The 85050B open pushes the centre contact to a defined position, so is more reproducible. The fringing capacitance is increased to around 100 fF.?
Obviously you need to have the cal kit set up properly.?
I do not have an open to sell.?
Regard
Tony Cheung
OCT 30 2018
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Re: HP85050A open standard 1250-1873 wanted
Dr. David Kirkby from Kirkby Microwave Ltd
Please On Tue, 30 Oct 2018, 14:05 Yiu On Tony C via Groups.Io, <tonycheung_hk= [email protected]> wrote: Hi members :
Anyone still using HP85050A with 1250-1873? open standard ??
Any photos or extra can offer ??
You might want to consider asking on?
In my 8510A have the cal. standard file A1. when cal. with 85050B can see the actually reading have some error in value measurement value ?
I compare DUT measured with my 8753E VNA .
Any advise ?
The 8753 uses the 85031 (from memory) which is a fairly simple standard with a waveguide beyond cutoff. A fringing capacitance around 82 fF is defined, but that is not very accurate as the fringing capacitance depends on the protrusion of the centre contact which is not well defined. Measure a few APC7 connectors with connector guages from the 85050B. I am unsure if the 85050A has guages.?
The 85050B open pushes the centre contact to a defined position, so is more reproducible. The fringing capacitance is increased to around 100 fF.?
Obviously you need to have the cal kit set up properly.?
I do not have an open to sell.?
Regard
Tony Cheung
OCT 30 2018
|
bownes
Michael A. Terrell
Yiu On Tony C