Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
Could you have used a single point frequency measurement n the VNA? I know the 8510 will do that.
But I am sure the experience was educational - thanks for the education - it would have taken me a bit of time to catch on to that.
Cheers!
Bruce
Quoting "Harke Smits via groups.io" <yrrah@...>:
toggle quoted message
Show quoted text
Hello,
There is one more issue to consider. Long lines give delays. Once I wanted to measure the loss of a coaxial cable on a vna. Was an interesting experience: no response. Until I realized the receiver had already traveled higher up in frequency at the time the response was back. You need to consider a delay in between frequency steps, long enough so as to give the receiver time to read the response. This is a documented feature (of course).
Good luck,
Harke, PA0HRK
On 26/05/2022 20:09, Tom Lee wrote:
Hi Karin,
"Upper limit" is not as hard a cliff as your question presupposes. Whether or not a given length of cable is too much depends on your acceptance criteria. What are you trying to measure, and to what accuracy do you need to measure it?
When you add cable, you get loss, so that loss subtracts directly from your dynamic range. For example, if you are making meaurements at a gigahertz or so, with RG-213 you can expect to lose about 10dB in each direction, roughly speaking. If you aren't trying to measure small deviations from an exquisitely well-matched load, you'll be fine. If you're trying to resolve small changes in the vicinity of a -60dB S11 null, then you may find the measurement challenging.
The other factor to consider with a long length of cable is that it isn't rigid, so stability of your measurement can be affected. And if you are doing a lengthy set of measurements, temperature effects can come into play as well. Whether these are "don't cares" or showstoppers depends on what you can tolerate. If you can tolerate large error bars, your measurement problems become much less severe. If you're trying to make publication-quality measurements, you may find that difficult.
Good luck!
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 5/26/2022 09:45, Karin Johnson 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
BTW: I have had an account on the Keysight forums in the past and have recently tried to login to that site, but It won't let me.? Possibly password have changed, and I cannot create a new account.? I have posted with Keysight support and hope they return the email.
|
Re: HP/Agilent/Keysight 8478B thermistor mount
I actually have one of these and treat it VERY carefully whenever I use it - which is infrequently
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
first of you have to consider that the 8478B just as the older 478 series requires a lot of manual assembly steps as it was designed in a time when there was no such thing as surface mount parts or automated assembly . one also has to consider that the QTY of those sold by keysight now is by far less than it was 10 or 20 years back ,? as bruce already pointed out those sensors nowadays are not mainstream anymore but rather used in calibration labs
|
Re: HP/Agilent/Keysight 8478B thermistor mount
I certainly would call $14K outrageously expensive.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
i wouldnt call it a transfer standard , weinschel/tegam makes sensors that use the same principle that are heated (1109/1111)? that are used with system 2 units to calibrate sensors , they are outrageously expensive
|
Re: HP 8662A Power up - overvoltage shutdown
Hi,
Following the comments by G Edmonds in this thread he recommended loading the PSU ?-40V rail more heavily to resolve the PSU shutdown error occurring immediately after start-up.
Pleased to say that seems to have done the trick - I loaded it with a 110mA current draw (that’s the only power resistor I had that was suitable) and it starts up ok at 230V where it would not beforehand - and the (pre-regulator) input rail has climbed from >-50V to just over -41V.
So I’m hoping that this PSU is actually working properly now, and it was my flawed testing approach that was the problem.
Thanks all for helpful advice and pointers. This groups is great.
Tony
|
Re: HP/Agilent/Keysight 8478B thermistor mount
On 5/26/22 16:10, Lothar baier wrote: i wouldnt call it a transfer standard , weinschel/tegam makes sensors that use the same principle that are heated (1109/1111)? that are used with system 2 units to calibrate sensors , they are outrageously expensive They certainly can be, and certainly are, used as transfer standards. Further, NIST will calibrate them. (they won't calibrate any other type of RF power sensor, unless something has changed very recently) -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
Re: HP/Agilent/Keysight 8478B thermistor mount
i wouldnt call it a transfer standard , weinschel/tegam makes sensors that use the same principle that are heated (1109/1111)? that are used with system 2 units to calibrate sensors , they are outrageously expensive?
|
Re: HP/Agilent/Keysight 8478B thermistor mount
first of you have to consider that the 8478B just as the older 478 series requires a lot of manual assembly steps as it was designed in a time when there was no such thing as surface mount parts or automated assembly . one also has to consider that the QTY of those sold by keysight now is by far less than it was 10 or 20 years back ,? as bruce already pointed out those sensors nowadays are not mainstream anymore but rather used in calibration labs?
|
Re: HP/Agilent/Keysight 8478B thermistor mount
It is directed at a captive audience. This piece is used as the transfer standard for making power measurement calibrations and is required for certain procedures. If you want to play in a certain arena, ou hve to have one. Obviously, HP does not sell too many of them which also leads to the huge cost.
Cheers!
bruce
Quoting Ken Eckert <eckertkp@...>:
toggle quoted message
Show quoted text
OMG, who would have thought......................
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
Hello,
There is one more issue to consider. Long lines give delays. Once
I wanted to measure the loss of a coaxial cable on a vna. Was an
interesting experience: no response. Until I realized the receiver
had already traveled higher up in frequency at the time the
response was back. You need to consider a delay in between
frequency steps, long enough so as to give the receiver time to
read the response. This is a documented feature (of course).
Good luck,
Harke, PA0HRK
On 26/05/2022 20:09, Tom Lee wrote:
toggle quoted message
Show quoted text
Hi Karin,
"Upper limit" is not as hard a cliff as your question presupposes.
Whether or not a given length of cable is too much depends on your
acceptance criteria. What are you trying to measure, and to what
accuracy do you need to measure it?
When you add cable, you get loss, so that loss subtracts directly
from your dynamic range. For example, if you are making
meaurements at a gigahertz or so, with RG-213 you can expect to
lose about 10dB in each direction, roughly speaking. If you aren't
trying to measure small deviations from an exquisitely
well-matched load, you'll be fine. If you're trying to resolve
small changes in the vicinity of a -60dB S11 null, then you may
find the measurement challenging.
The other factor to consider with a long length of cable is that
it isn't rigid, so stability of your measurement can be affected.
And if you are doing a lengthy set of measurements, temperature
effects can come into play as well. Whether these are "don't
cares" or showstoppers depends on what you can tolerate. If you
can tolerate large error bars, your measurement problems become
much less severe. If you're trying to make publication-quality
measurements, you may find that difficult.
Good luck!
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 5/26/2022 09:45, Karin Johnson
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??
BTW: I have had an account on the Keysight forums in the past
and have recently tried to login to that site, but It won't let
me.? Possibly password have changed, and I cannot create a new
account.? I have posted with Keysight support and hope they
return the email.?
|
Re: HP 8662A Power up - overvoltage shutdown
Dan -
Excellent ob - maybe you should publish the Gerber Files for the new motherboard ?
Cheers!
Bruce
Quoting "Daniel Nelson via groups.io" <djn@...>:
toggle quoted message
Show quoted text
|
Re: HP/Agilent/Keysight 8478B thermistor mount
OMG, who would have thought......................
|
HP/Agilent/Keysight 8478B thermistor mount
For those of you who possess the older (hopefully working and accurate) 478A coaxial thermistor mount it might come as a surprise that the price of the present replacement – the Keysight 8478B mount – has again risen a few hundred $$ to $14,100.
?
That is a real incentive to treat your present mount with kindness and respect and not let it roll off of the bench.
?
Greg
|
Re: HP 8662A Power up - overvoltage shutdown
Tony: I also replaced the power supply with a group of Meanwell Supplies. Wrote it up. In the files section under: HP 8662A_8663A Pwr Supply Changeout.pdf? What I found is that the design of the main switcher is problematic as almost 500 watts of power has to be transmitted through two 22uF capacitors and they do get cooked after awhile which leads to killing the power transistors. I got tired of chasing that..... Dan in Chandler, AZ?
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
One thing to consider is that RG213 is not phase stable so if you flex the cable after calibration it may affect your measurement
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of Tom Lee via groups.io
Sent: Thursday, May 26, 2022 1:10 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Limits of the Port Extension on the Cal screen for calibrating at end of cable
?
Hi Karin,
"Upper limit" is not as hard a cliff as your question presupposes. Whether or not a given length of cable is too much depends on your acceptance criteria. What are you trying to measure, and to what accuracy do you need to measure it?
When you add cable, you get loss, so that loss subtracts directly from your dynamic range. For example, if you are making meaurements at a gigahertz or so, with RG-213 you can expect to lose about 10dB in each direction, roughly speaking. If you aren't trying
to measure small deviations from an exquisitely well-matched load, you'll be fine. If you're trying to resolve small changes in the vicinity of a -60dB S11 null, then you may find the measurement challenging.
The other factor to consider with a long length of cable is that it isn't rigid, so stability of your measurement can be affected. And if you are doing a lengthy set of measurements, temperature effects can come into play as well. Whether these are "don't cares"
or showstoppers depends on what you can tolerate. If you can tolerate large error bars, your measurement problems become much less severe. If you're trying to make publication-quality measurements, you may find that difficult.
Good luck!
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 5/26/2022 09:45, Karin Johnson 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??
BTW: I have had an account on the Keysight forums in the past and have recently tried to login to that site, but It won't let me.? Possibly password have changed, and I cannot create a new account.? I have posted with Keysight support and hope they return the
email.?
?
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
Hi Karin,
"Upper limit" is not as hard a cliff as your question presupposes.
Whether or not a given length of cable is too much depends on your
acceptance criteria. What are you trying to measure, and to what
accuracy do you need to measure it?
When you add cable, you get loss, so that loss subtracts directly
from your dynamic range. For example, if you are making meaurements
at a gigahertz or so, with RG-213 you can expect to lose about 10dB
in each direction, roughly speaking. If you aren't trying to measure
small deviations from an exquisitely well-matched load, you'll be
fine. If you're trying to resolve small changes in the vicinity of a
-60dB S11 null, then you may find the measurement challenging.
The other factor to consider with a long length of cable is that it
isn't rigid, so stability of your measurement can be affected. And
if you are doing a lengthy set of measurements, temperature effects
can come into play as well. Whether these are "don't cares" or
showstoppers depends on what you can tolerate. If you can tolerate
large error bars, your measurement problems become much less severe.
If you're trying to make publication-quality measurements, you may
find that difficult.
Good luck!
--Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 5/26/2022 09:45, Karin Johnson
wrote:
toggle quoted message
Show quoted text
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??
BTW: I have had an account on the Keysight forums in the past and
have recently tried to login to that site, but It won't let me.?
Possibly password have changed, and I cannot create a new
account.? I have posted with Keysight support and hope they return
the email.?
|
Re: Limits of the Port Extension on the Cal screen for calibrating at end of cable
You mention port extensions but then in the post you refer to calibration ,? I just want to point out that those are different things !
When you do a calibration on a VNA you move the reference plane to the reference plane of your connector/cal standard no other adjustments are needed.
Port extensions are a software correction that are normally used to move the reference plane AFTER a calibration has been performed , this is typically done when you work with fixtures or other situations where a calibration is not practical
or possible
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of Karin Johnson via groups.io
Sent: Thursday, May 26, 2022 11:46 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] Limits of the Port Extension on the Cal screen for calibrating at end of cable
?
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??
BTW: I have had an account on the Keysight forums in the past and have recently tried to login to that site, but It won't let me.? Possibly password have changed, and I cannot create a new account.? I have posted with Keysight support and hope they return the
email.?
|
Re: Info Need on a RF FET for a Agilent E4438C signal generator
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
?
?
toggle quoted message
Show quoted text
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
|
Limits of the Port Extension on the Cal screen for calibrating at end of cable
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??
BTW: I have had an account on the Keysight forums in the past and have recently tried to login to that site, but It won't let me.? Possibly password have changed, and I cannot create a new account.? I have posted with Keysight support and hope they return the email.?
|
Re: E4407B RYTHM Repair / Replace
Hello Kalle and Bob I worked out a method of adjusting a bad RYTHM tower. That works for the HP8563E and for the E4407. They share the tower as far as I know.
Problem is the E4407 cannot be calibrated withot special software that is not available.
After a Tower adjust it is needed to adjust the flattness over the band from 2.9 to 26.5Ghz
best regards Peter
Hi Bob,
I am working on my own RYTHM with some success.
Can you do the following:
Insert CW at 4GHz, -20dBm.
Apply the following settings on E4407B:
Center freq 4GHz
Span 250MHz
Resolution BW 1MHz, Video BW 1MHz
Preselector Center: Front Panel Access: AMPLITUDE/Y Scale, Presel Center
Do you get a peak of reasonable amplitude at 4GHz after this?
If you do, then your YTF polynomial might be off. I am working on a procedure for this.
Best regards
|
Re: 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
?
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of Peter Hansen via groups.io
Sent: Wednesday, May 25, 2022 4:16 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] Info Need on a RF FET for a Agilent E4438C signal generator
?
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
|
Dave McGuire