Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
On Sat, 28 May 2022 at 00:50, Karin Johnson < karinann@...> wrote: I realized a couple of hours after sending the initial post, that I was incorrect with associating Calibration with the Port Extensions.
Here is, I hope a better explanation of what I am trying to do.
First off the measurement frequency is 14 MHz.? So not too beyond the capability of the 8753C.
? A wavelength of roughly 20 m.
I want to place the measurement plane at the end of a 100 foot length of RG213.? ? Em, wish you would work in metric! Let's call that 30 m. So your cable
is 1.5 wavelengths long, which is far from unusual for a VNA.? My 20 GHz
VNA has cables that are 600 mm long, so 40 wavelengths. It calibrates okay, with cables 40 wavelengths long.
So I place the SOL standards, one at a time at the
end of the cable.? Supposedly the 8753C measurement plane is now at the end of the cable.
? More precisely, at the reference plane of the connector on the end of your cable. Depending on the connector, the reference plane may or may not be near the end of the connector. The reference plane of the connector is the outer conductor mating plane. In the case of a female N, it is well inside the connector - roughly 8 mm, as I measured with a bit of wire and ruler next to me. ????
Now I can take S11 measurements relative to the measurement plane at the end of the cable.? My question should have been
" Is there a limit in terms of how long a cable can be before this calibration technique fails."
This is probably related to the storage of the cal correction factors in the memory of the 8753C.? Is it via floating point numbers, or integer numbers?
How large or small can the calibration correction values be???
? The calibration factors to be entered into the VNA include the offset delays (lengths) of the calibration standards. They are only of the order of mm. The fact your cable is 100 m long does not change those numbers.
I seem to be able to obtain valid data using this technique, but wanted to ask on the Keysight forum with some of the folks who actually designed
the instrument.? I think Dr. Joel it still active there.? ?
I would certainly slow the sweep speed down, and see if that changes your results. If it does, then you have a problem.
?
My rant about not being able to login to the Keysight forums still exists.? It seems their login/validation screen seems broken.
At one time I had an account over there but they have seemed to have changed the supporting vendor for the forum sites.
I wish Keysight would just use some open-source forum software, instead of all this proprietary crap, which they keep needing to change.?
As always,
Regards,
Karin Johnson
? Dave
|
If you are unable to find exact replacements, many have successfully
improvised substitutes. I've used the contact fingers from cast-off
solderless breadboards and Lothar's method of screwing them down.
They don't look pretty, but they work fine.
Good luck, The self-disassembling contact fingers is a fairly common
problem in a certain vintage of HP products (HP8557A/8558A, just to
name a couple others).
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 5/28/2022 08:06, Donald Prins wrote:
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Hi Ellud,
Can you tell me where one can obtain those wipers? I have a
HP8640B that is missing 3 in total on the FM/RANGE switches. Your
help will be much appreciated.
Donald?
PE1AHJ
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
On Sat, 28 May 2022 at 02:22, Tom Lee < tomlee@...> wrote: As far as I am aware, the port extension feature only adds pure phase.
You enter a delay parameter, or a physical length + velocity factor. I
don't recall ever seeing any option to dial in any other parameters
(e.g., loss), but that may be due to my rarely using port extensions,
and then only to shift the reference plane by tiny amounts.
--Tom
--
Prof. Thomas H. Lee
That's true on the 8753, but the PNA-X, and probably some lesser instruments, allow loss to be added too. But no port extension is needed here.
Dave
|
A very similar style of these ‘finger’ contact is found in the 8011/12/13 pulse generators which can be found quite cheaply…. How do i know… just repaired one… works lovely.
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On 28 May 2022, at 22:01, n4buq <n4buq@...> wrote:
? Other HP switches use those wipers.? I think some of the slide switches on the 8640B use them but I think there are others too.
Thanks,
Barry - N4BUQ
From: "Donald Prins" <dyhprins@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Saturday, May 28, 2022 10:06:01 AM
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B no rf out
Hi Ellud,
Can you tell me where one can obtain those wipers? I have a HP8640B that is missing 3 in total on the FM/RANGE switches. Your help will be much appreciated.
Donald?
PE1AHJ
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
On Thu, 26 May 2022 at 17:45, Karin Johnson < karinann@...> wrote: Hello Group:
I have an 8753C and am wondering what the upper limit on cable length would be if I place the cal standards at the end of a cable to do remote measurement of S11.?? In other words I am using SOL, with the cal standards placed at the end of a 100 foot length of RG-213.? Theoretically placing the measurement plane at the end of the cable.? I have already done this and the results seem to be accurate relative to an actual measurement at the that physical place.
I hope I have explained this issue sufficiently.?
Regards,
Karin Johnson??
In addition to the points raised by others, there is another factor to consider. You will need to slow the sweep speed down, below that automatically chosen for you. Otherwise the frequency of the oscillator will have shifted outside the passband of the receiver by the time it gets back to the receiver. This is well documented in one of the HP Application notes.
Dave
|
Other HP switches use those wipers.? I think some of the slide switches on the 8640B use them but I think there are others too.
Thanks,
Barry - N4BUQ
From: "Donald Prins" <dyhprins@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Saturday, May 28, 2022 10:06:01 AM
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B no rf out
Hi Ellud,
Can you tell me where one can obtain those wipers? I have a HP8640B that is missing 3 in total on the FM/RANGE switches. Your help will be much appreciated.
Donald?
PE1AHJ
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
One more comment regarding maximum cable length. If you have option 010 (time domain), there is a limit to the time interval you can display, but I think that's tied to the math for the transform. Just to make sure that there is no such problem in the frequency domain, compare your measurement with a small number of points with a measurement with the maximum number of points. If you pick some low number of points (e.g. 11) and the analyzer no longer gives good results, it's because it couldn't make sense of "N".
Vladan
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
Karin,
As I understand your question, you are concerned that the calibration data for a long cable requires larger numerical values due to the many 360 degree repeats of the phase.
The analyzer determines the “N” in N*360 by looking a the series of points rather than at a single frequency value. If you were to measure phase at one frequency only, the analyzer would not know if N=1 or N=10000000. It would merely give you a value within one 360 degree range.
The main thing to be aware of is the delay, as Harke mentioned. I would make this measurement using the “LIST” (or "stepped")? sweep and I would slow the sweep speed down as much as necessary to get to a point of diminishing returns. For the same reason, using a narrow IF bandwidth makes things worse.
The other problem is what Tom mentioned, the cable loss reduces your dynamic range.
Vladan
|
Based on recent painful experience, I've discovered a couple of things:
1. Some ISPs block based on listing in some questionable databases. In particular, the "UCEPROTECT" lists range from including just the sender IP, to the whole subnet of that IP, to the whole ASN (assigned network number) of that IP, which can block millions of addresses. Smart ISPs assign only some weight in their spam filters to databases like that. But it seems not all are smart, or they get accidentally misconfigured. Our ISP recently had a big fight with MSFT over this.
2. Big ISPs like Google and Microsoft have gotten more picky about the sending system having correct DMARC, DKIM, and SPF records in their DNS. If you have your own domain and set up your own DNS, you may not have those records set up. That didn't used to matter much, but we just solved several problems by getting our records fixed (we had some outdated info after our ISP made changes to their system).
John
----
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On 5/28/22 14:18, Paul Amaranth wrote: Actually, that means the IP of your email server is blocklisted. If
you do a reverse lookup on that, it resolves to mail-pj1-f53.google.com.
You can look up IPs on line to see which, if any, blocklist it appears
in. A couple sites are mxtoolbox.com and www.debounder.com. This server
does appear in a two or three blocklists.
What you need to do is contact whomever manages your email system and have
them apply to be removed from the blocklist. This has to be from
an administrator of the domain, not a user, and any spam issues have to
be corrected.
Sometimes there may be some configuration issues at the mailer that
rejects the mail. On my system I was getting transient blocklist failures
rejecting perfectly valid senders and I had to disable that feature.
Paul
On Sat, May 28, 2022 at 07:52:43AM -0600, John Griessen wrote:
On 5/27/22 18:03, Matt Huszagh wrote:
[209.85.216.53]:42889 is in an RBL This means your IP is blacklisted. is there a URL for remedy in the message? You can ask to be unblacklisted.
It can be because your ISP allows too many bad customers sometimes.
!DSPAM:62922936133621664620935!
|
On Sat, May 28, 2022 at 02:18:47PM -0400, Paul Amaranth wrote: Actually, that means the IP of your email server is blocklisted. If
you do a reverse lookup on that, it resolves to mail-pj1-f53.google.com.
You can look up IPs on line to see which, if any, blocklist it appears
in. A couple sites are mxtoolbox.com and www.debounder.com. This server
does appear in a two or three blocklists. Oops, typo. That was www.debouncer.com -- Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@... | Unix/Linux - We don't do windows
|
Actually, that means the IP of your email server is blocklisted. If
you do a reverse lookup on that, it resolves to mail-pj1-f53.google.com.
You can look up IPs on line to see which, if any, blocklist it appears
in. A couple sites are mxtoolbox.com and www.debounder.com. This server
does appear in a two or three blocklists.
What you need to do is contact whomever manages your email system and have
them apply to be removed from the blocklist. This has to be from
an administrator of the domain, not a user, and any spam issues have to
be corrected.
Sometimes there may be some configuration issues at the mailer that
rejects the mail. On my system I was getting transient blocklist failures
rejecting perfectly valid senders and I had to disable that feature.
Paul
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On Sat, May 28, 2022 at 07:52:43AM -0600, John Griessen wrote:
On 5/27/22 18:03, Matt Huszagh wrote:
[209.85.216.53]:42889 is in an RBL This means your IP is blacklisted. is there a URL for remedy in the message? You can ask to be unblacklisted.
It can be because your ISP allows too many bad customers sometimes.
!DSPAM:62922936133621664620935!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
|
Re: checking line module setting for 110V / 220V
Many thanks for your great feedback.
It gave me enough courage to pull the little card out.
I found I had a pair of pincers with a hook on the tip.
No idea what it was originally for, but worked great.
:-)
Best regards,
Tom
|
The 8557/58/59 used the same kind of disks you could possibly find a parts mule on ebay though there is no guarantee that its not going to suffer from the same disease as this was a common problem.
Take note though that the springs are attached to the disks by means of small plastic bumps that are molted to secure them , thermoplastics become briddle over time and the bumps shear off.
The way i fixed them back at tucker was to get small self tapping screws and use a dremel tool to drill holes in the disks
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On May 28, 2022, at 11:28, kim.herron@... via groups.io <kim.herron@...> wrote:
?
You can try contacting Sphere Research in Vancouver BC, Canada.? They have a lot of HP parts.? Those wipers are part of the discs that are in the switch assy and no part number exists
for the wipers as such.? However, there may be other HP gear that uses something similar that would yield the items that you need to fix your generator.? You can also keep an eye out for an entire
switch assy from an 8640B on E-Bay.? That stuff is out there.? The reason that those wipers break off is because of the gears cracking.? Those cracked gears force the tension spring
in the rear of that switch assy? to collapse and when that happens the wipers on those discs are forced to flex beyond their design limits and that's what breaks them off the discs.? Make sure your gears are not coming apart.
On 28 May 2022 at 8:06, Donald Prins wrote:
Hi Ellud,
Can you tell me where one can obtain those wipers? I have a HP8640B that is missing 3 in total on the FM/RANGE switches. Your help will be much appreciated.
Donald?
PE1AHJ
Kim Herron? W8ZV
kim.herron@...????
1-616-677-3706
|
You can try contacting Sphere Research in Vancouver
BC, Canada.? They have a lot of HP parts.? Those wipers
are part of the discs that are in the switch assy and no
part number exists for the wipers as such.? However,
there may be other HP gear that uses something similar
that would yield the items that you need to fix your
generator.? You can also keep an eye out for an entire
switch assy from an 8640B on E-Bay.? That stuff is out
there.? The reason that those wipers break off is because
of the gears cracking.? Those cracked gears force the
tension spring in the rear of that switch assy? to collapse
and when that happens the wipers on those discs are
forced to flex beyond their design limits and that's what
breaks them off the discs.? Make sure your gears are not
coming apart.
On 28 May 2022 at 8:06, Donald Prins wrote:
Hi Ellud,
Can you tell me where one can obtain those wipers? I
have a HP8640B that is missing 3 in total on the
FM/RANGE switches. Your help will be much
appreciated.
Donald?
PE1AHJ
Kim Herron? W8ZV
kim.herron@...????
1-616-677-3706
|
In the archive you will find discussion of this, including at least one account of improvising new contacts out of something else.
?
Dave Wise
?
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From: [email protected] < [email protected]>
On Behalf Of Donald Prins via groups.io
Sent: Saturday, May 28, 2022 8:06 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B no rf out
?
Hi Ellud,
Can you tell me where one can obtain those wipers? I have a HP8640B that is missing 3 in total on the FM/RANGE switches. Your help will be much appreciated.
Donald?
PE1AHJ
|
Hi Ellud,
Can you tell me where one can obtain those wipers? I have a HP8640B that is missing 3 in total on the FM/RANGE switches. Your help will be much appreciated.
Donald?
PE1AHJ
|
On 5/27/22 18:03, Matt Huszagh wrote: [209.85.216.53]:42889 is in an RBL This means your IP is blacklisted. is there a URL for remedy in the message? You can ask to be unblacklisted. It can be because your ISP allows too many bad customers sometimes.
|
Re: Info Need on a RF FET for a Agilent E4438C signal generator
Its a common issue that you have a lot of excess gain at lower frequencies and then roll off at higher frequencies normally you can combat this by using resistive feedback between drain and gate , it will change your input impedance and drop gain at lower frequencies!
I think the best approach would be to find a MMIC that will work , i looked through offerings from different companies and nobody seems to make discretes in SOT89 anymore?
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On May 28, 2022, at 03:13, Peter Hansen via groups.io <oz1lpr@...> wrote:
?
Hello Lothar I do not need 27dBm output. As it is not the final Fet. but I think the gain of the SHF-0189 is too little. It has around 20dB at low freq but only 10 to 12dB at 4Ghz. so I might need more gain
best regards Peter
The problem is finding a HEMT in SOT89 with 27dBm ,? used to those parts were made as driver or pre-driver for Power amps but this is all done with MMIC now ,? I remember seeing a GaN HEMT made by MACOM that was SOT89 but I believe it
was a 28V part !
?
As far as MMIC you can try the TQP7M9103 , its specified 400-4000MHz but you can use it at lower frequencies , this part does require external matching and only produces 13-14Db gain at 4GHz but can drive 27dBm
?
?
?
Hello Lothar It is a Fet. I does have a biasing system where is measures to drop over the Drain supply and then give bias to the Gate. The circuit does include matching network. I added a SHF-0189
in the circuit and it works but too low output for the High output option mounted. I can find traces on the Net over the M11X but only that it is a HFET.
The Fet is in the ALC loop so the amplitude is not really a problem as long as there is enough. I am afraid that is not the case. I wonder if a MMIC would work in the spot. I need one working
from 250khz to 4Ghz. the 4 to 6Ghz path is another board so the Part only need to go to 4Ghz.
sorry no schematics over the E44XX series
best regards Peter OZ1LPR
Do you have the schematic of the stage ?? if so can you share it ?
Let me render a few comments / thoughts on this :
- The first thing that needs to be established is whether the original part is a FET or a MMIC amplifier ,? you can tell by looking at the schematics , if there is a bias applied to both input and output
or just the output of the block , if bias is only applied to the output than its more than likely a MMIC amplifier if bias exists on both gate and drain than it’s a FET/HEMT !
- If the part is a FET than there should be matching as well as feedback networks present , since this is a stage operating over a wide frequency range resistive feedback between gate and drain will most
certainly be required in addition to lumped input and output matching circuits
- Based on the gain and output power estimate you provided as well as the frequency range of the generator I question the assessment of this part being a FET and rather assume this being a MMIC as it would
be hard to reach 20Db gain and 27dBm P1Db up to 4GHz
- If the part is a FET using matching networks it will be hard to find a drop in replacement , if you were to find a part in a SOT-89 package you will most certainly have to re-design the matching networks
as S-parameters will be different
?
?
?
I am rapiring a E4438C generator. There is a FET shorted in the output of chain of the 4Ghz path. The FET is called M11X1005. I can see traces of it existing
but no data. The SHF-0189Z can be used but not directly. The M11X1005 is using 6.5V on the drain but the SHF-0189 uses 8V and has higher gain and higher output.
Does anyone have either a M11X1005 Fet, data or a suitable repleacement.
I would assume something having 20dB of gain and +27dBm output.
best regards Peter
|
Re: Info Need on a RF FET for a Agilent E4438C signal generator
Hello Lothar I do not need 27dBm output. As it is not the final Fet. but I think the gain of the SHF-0189 is too little. It has around 20dB at low freq but only 10 to 12dB at 4Ghz. so I might need more gain
best regards Peter
The problem is finding a HEMT in SOT89 with 27dBm ,? used to those parts were made as driver or pre-driver for Power amps but this is all done with MMIC now ,? I remember seeing a GaN HEMT made by MACOM that was SOT89 but I believe it
was a 28V part !
?
As far as MMIC you can try the TQP7M9103 , its specified 400-4000MHz but you can use it at lower frequencies , this part does require external matching and only produces 13-14Db gain at 4GHz but can drive 27dBm
?
?
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From: [email protected] < [email protected]>
On Behalf Of Peter Hansen via groups.io
Sent: Thursday, May 26, 2022 11:23 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Info Need on a RF FET for a Agilent E4438C signal generator
?
Hello Lothar It is a Fet. I does have a biasing system where is measures to drop over the Drain supply and then give bias to the Gate. The circuit does include matching network. I added a SHF-0189
in the circuit and it works but too low output for the High output option mounted. I can find traces on the Net over the M11X but only that it is a HFET.
The Fet is in the ALC loop so the amplitude is not really a problem as long as there is enough. I am afraid that is not the case. I wonder if a MMIC would work in the spot. I need one working
from 250khz to 4Ghz. the 4 to 6Ghz path is another board so the Part only need to go to 4Ghz.
sorry no schematics over the E44XX series
best regards Peter OZ1LPR
Do you have the schematic of the stage ?? if so can you share it ?
Let me render a few comments / thoughts on this :
- The first thing that needs to be established is whether the original part is a FET or a MMIC amplifier ,? you can tell by looking at the schematics , if there is a bias applied to both input and output
or just the output of the block , if bias is only applied to the output than its more than likely a MMIC amplifier if bias exists on both gate and drain than it’s a FET/HEMT !
- If the part is a FET than there should be matching as well as feedback networks present , since this is a stage operating over a wide frequency range resistive feedback between gate and drain will most
certainly be required in addition to lumped input and output matching circuits
- Based on the gain and output power estimate you provided as well as the frequency range of the generator I question the assessment of this part being a FET and rather assume this being a MMIC as it would
be hard to reach 20Db gain and 27dBm P1Db up to 4GHz
- If the part is a FET using matching networks it will be hard to find a drop in replacement , if you were to find a part in a SOT-89 package you will most certainly have to re-design the matching networks
as S-parameters will be different
?
?
?
I am rapiring a E4438C generator. There is a FET shorted in the output of chain of the 4Ghz path. The FET is called M11X1005. I can see traces of it existing
but no data. The SHF-0189Z can be used but not directly. The M11X1005 is using 6.5V on the drain but the SHF-0189 uses 8V and has higher gain and higher output.
Does anyone have either a M11X1005 Fet, data or a suitable repleacement.
I would assume something having 20dB of gain and +27dBm output.
best regards Peter
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
As far as I am aware, the port extension feature only adds pure phase. You enter a delay parameter, or a physical length + velocity factor. I don't recall ever seeing any option to dial in any other parameters (e.g., loss), but that may be due to my rarely using port extensions, and then only to shift the reference plane by tiny amounts.
--Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
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On 5/27/2022 18:12, Dave McGuire wrote: On 5/27/22 19:50, Karin Johnson wrote:
This is probably related to the storage of the cal correction factors in the memory of the 8753C.? Is it via floating point numbers, or integer numbers? ? I don't know about the 8753 in particular, but for the 8510, for example, the calibration correction factors are floating point numbers that are the coefficients for the third-order polynomial that describes the curve (C or L) in the frequency domain for the calibration standard in question.? I'd be very surprised if the 8753 did it any differently.
? Dave Kirkby should be able to chime in on this with more information.
??????????? -Dave
|
Dr. David Kirkby, Kirkby Microwave Ltd