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Hi Bob… ? Got ‘em. Thanks! ? Tom, N8ZM ?
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From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io> On Behalf Of Bob Stewart
Sent: Saturday, March 12, 2022 6:36 PM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters? Is this what you're looking for by any chance? | 
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On Wednesday, March 9, 2022, 1:03:13 AM CST, Lothar baier <lothar@...> wrote: Oh I was not talking about myself, I have calibrated power sensors and meters this was just for people to consider?
On Mar 9, 2022, at 00:07, n8zmTWH via groups.io <n8zmTWH@...> wrote:
A couple of thoughts on that… ? It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you. ? Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes, you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA markers are more accurate than eyeballs. ? It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however. ? Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily testing. ? BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one. ? ? the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have a calibrated sensor there was no need to design a sensor?
|
Lothar,
Is this what you're looking for by any chance?
On Wednesday, March 9, 2022, 1:03:13 AM CST, Lothar baier <lothar@...> wrote:
Oh I was not talking about myself, I have calibrated power sensors and meters this was just for people to consider?
On Mar 9, 2022, at 00:07, n8zmTWH via groups.io <n8zmTWH@...> wrote:
?
A couple of thoughts on that…
?
It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you.
?
Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes,
you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA
markers are more accurate than eyeballs.
?
It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are
calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however.
?
Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily
testing.
?
BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even
the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one.
?
From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io>
On Behalf Of Lothar baier
Sent: Wednesday, March 09, 2022 12:37 AM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters
?
the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have
a calibrated sensor there was no need to design a sensor?
|
Understood ,
Generally if I were to pursue a sensor design I would design a USB sensor rather than pursuing a replacement for a existing sensor , there are small mixed signal Processors with USB such as CYPRESS PSOC that can be used , for the sensing
element I would use analog devices detector mmic which are cheap and readily available or for higher frequency a self balancing bridge design using thermistors or a thermal sensor design
?
Back when I was a teen getting started with microwave ham radio I build my first powermeter using a thermal bridge ,? the design used a 50ohm chip termination with a thermistor attached using thermal conductive glue , the thermistor was
put in a bridge circuit and used a DMM module for readout , the beauty of this design was that you could do a rough calibration using a DMM and DC power supply
?
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From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io>
On Behalf Of n8zmTWH via groups.io
Sent: Wednesday, March 9, 2022 7:58 AM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters
?
I didn’t think you were. My ‘you’ was just a general case.
?
?
Oh I was not talking about myself, I have calibrated power sensors and meters this was just for people to consider?
On Mar 9, 2022, at 00:07, n8zmTWH via groups.io <n8zmTWH@...> wrote:
?
A couple of thoughts on that…
?
It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you.
?
Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes,
you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA
markers are more accurate than eyeballs.
?
It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are
calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however.
?
Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily
testing.
?
BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even
the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one.
?
?
the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have
a calibrated sensor there was no need to design a sensor?
|
I didn’t think you were. My ‘you’ was just a general case. ?
toggle quoted message
Show quoted text
From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io> On Behalf Of Lothar baier
Sent: Wednesday, March 09, 2022 2:03 AM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters? Oh I was not talking about myself, I have calibrated power sensors and meters this was just for people to consider?
On Mar 9, 2022, at 00:07, n8zmTWH via groups.io <n8zmTWH@...> wrote:
? A couple of thoughts on that… ? It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you. ? Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes, you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA markers are more accurate than eyeballs. ? It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however. ? Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily testing. ? BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one. ? ? the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have a calibrated sensor there was no need to design a sensor?
|
Oh I was not talking about myself, I have calibrated power sensors and meters this was just for people to consider?
toggle quoted message
Show quoted text
On Mar 9, 2022, at 00:07, n8zmTWH via groups.io <n8zmTWH@...> wrote:
?
A couple of thoughts on that…
?
It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you.
?
Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes,
you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA
markers are more accurate than eyeballs.
?
It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are
calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however.
?
Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily
testing.
?
BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even
the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one.
?
From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io>
On Behalf Of Lothar baier
Sent: Wednesday, March 09, 2022 12:37 AM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters
?
the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have
a calibrated sensor there was no need to design a sensor?
|
A couple of thoughts on that… ? It assumes you don’t have friends with a suitable sensor, or are unwilling to pay a commercial cal house to do it for you. ? Also, if you have a decent SA and sig gen that you have reasonable faith in, those can be used, Yes, they aren’t quite as good as having another sensor, but for hobby purposes, you could get within a half dB with care and decent gear. If you have both the SA and SG, you now have two reference instruments, and if they are in agreement then you can be fairly confident of your cal. Most SG’s provide output level indications, and SA markers are more accurate than eyeballs. ? It should be noted that power meters are the most accurate devices for power measurements, if traceable to NIST or equivalent. Typically less than .2 dB uncertainty. SG’s are calibrated for output power with a power meter. The 8566 is +/- 1 dB or more over its frequency range (from memory). More modern SA’s, such as the PSA and PXA series, can almost match a power meter for uncertainty, however. ? Building a sensor as a challenge is a good exercise even if you have a real one. You could keep the real one on the shelf as a reference and use the homebrewed unit for you daily testing. ? BTW, I am trying to revive an really old HP sensor from the 60’s that used 4 AGX 0.01 amp fuses as the sense and reference elements. So far they appear to be unobtanium. Even the fuse makers don’t list them anymore and I haven’t yet found anything that looks to be equivalent. Just finding a 0.01 amp fuse in any style is a tough one. ?
toggle quoted message
Show quoted text
From: HP-Agilent-Keysight-equipment@groups.io <HP-Agilent-Keysight-equipment@groups.io> On Behalf Of Lothar baier
Sent: Wednesday, March 09, 2022 12:37 AM
To: HP-Agilent-Keysight-equipment@groups.io
Subject: Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters? the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have a calibrated sensor there was no need to design a sensor?
|
the problem you run into when developing any substitute sensor ,? which is calibration , in order for a sensor to be of value you have to calibrate it which usually is done by comparing it to a calibrated sensor but obviously if you have a calibrated sensor there was no need to design a sensor?
|
Does anyone now how to contact Tobias Pluess? My email got bounced.
Nothing to do with this issue. Tobias please email me off line. Peter
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This has been an interesting thread. Like everyone lots of dead power sensors. Whats funny is now even the dead sensors seem to have magical value. The actual meters are nice. Something about a analog readout for peaking power while tuning. But that said I do agree that the modern ic power sensors good to about 6 Ghz seem like a reasonable fit. But I believe that most of the circuits used in the meter may not be needed. If I get around to this I would tend to set the gain of a opamp in the meter through the db switch. The sensors have a predictable voltage out. A small?part of that range needs to be mapped into each power switch range. Easier said than done. The alternative and I think perhaps far harder is to compress the IC sensor into what a diode would have put out. Then use the chopper and such as is. Best of luck to anyone who goes further. Regards Paul
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Make on a lot of sense, please some diagram for it.
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On 5/31/21 9:35 AM, Francesco wrote: The output of the detector AD8318/17 is positive any idea to make it
negative? Please diagram I'm one geriatric old man. How about an op-amp configured as an inverting amplifier? -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Hello Tobias, some information for your diode power sensor please.
Best regards.
Francesco.
G7OYO
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The output of the detector AD8318/17 is positive any idea to make it negative? Please diagram I'm one geriatric old man.
Regards.
Francesco.
G7OYO
|
Thank you Dave for the imput to this post, I'm aware there is some difficulty fot the detectot part on the power head.
I hope if there someone want share is exsperience and like give some sugestion and diagram to help to build one will be apreciate.
Francesco.
G7OYO
?
?
Sent:?Sunday, May 30, 2021 at 6:47 PM
From:?"Dave McGuire" <mcguire@...>
To:?HP-Agilent-Keysight-equipment@groups.io
Subject:?Re: [HP-Agilent-Keysight-equipment] A homemade diode power sensor for HP meters
On 5/30/21 1:14 PM, Francesco wrote:
> This topic is on the dead track?? It is one very interesting topic,
> considering there is one Hi number of HP 435, 436, 437 models for a low
> price is a good opportunity for small lab and student on the RF world to
> grab one of these simple instrument for 50/100 pounds, the big problem
> the second-hand market is on the hand of surplus scavengers they sell
> the hold and rusty powerhead at Hi price.
> Way no make one at a low price and nice fun to handmade one with some
> good result making a one-hybrid system like es: detector AD8318/17 the
> chopper, and the amplifier using the 8484A diagram using the chopper FET
> circuit and the NPN Transistor amplifier.
Some people have done this. I had something very much like this
running in a bench test configuration several years ago. It worked
reasonably well, but not well enough to productize, and there were still
unresolved problems. The power sensor interface is simple, but not
quite as simple as it looks.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
?
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On 5/30/21 1:14 PM, Francesco wrote: This topic is on the dead track?? It is one very interesting topic,
considering there is one Hi number of HP 435, 436, 437 models for a low
price is a good opportunity for small lab and student on the RF world to
grab one of these simple instrument for 50/100 pounds, the big problem
the second-hand market is on the hand of surplus scavengers they sell
the hold and rusty powerhead at Hi price.
Way no make one at a low price and nice fun to handmade one with some
good result making a one-hybrid system like es: detector AD8318/17 the
chopper, and the amplifier using the 8484A diagram using the chopper FET
circuit and the NPN Transistor amplifier. Some people have done this. I had something very much like this running in a bench test configuration several years ago. It worked reasonably well, but not well enough to productize, and there were still unresolved problems. The power sensor interface is simple, but not quite as simple as it looks. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
|
This topic is on the dead track?? It is one very interesting topic, considering there is one Hi number of HP 435, 436, 437 models for a low price is a good opportunity for small lab and student on the RF world to grab one of these simple instrument for 50/100 pounds, the big problem the second-hand market is on the hand of surplus scavengers they sell the hold and rusty powerhead at Hi price.
Way no make one at a low price and nice fun to handmade one with some good result making a one-hybrid system like es: detector AD8318/17 the chopper, and the amplifier using the 8484A diagram using the chopper FET circuit and the NPN Transistor amplifier.
If you need one power meter to make money BUY one 12.000 meters, but for hobby student and small lab the approach of Tobias whos the good one.
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Hello, I follow your topic on the homemade diode power sensor for HP meters, please can I get the diagram to make one? I buy one HP436A but no sensor.
Thank you in advance, Francesco.
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After a couple of seconds of stupidity eighteen months ago, I could certainly be interested in looking at, and perhaps contributing to, the design of an internal PCB for an 8484 which lies dismantled, waiting for either a working replacement capsule or a reproducible, compatible, (diode-based) detector design.
Compliments of the season to all!
Chris Bartram
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Any significant differences between the HP 5347/8's for use with the power sensors?? ?I'll read through the attached links and data again later this winter once the snow falls.? Saved for now.?
From my newbie limited background; seems the old Pacific Measurements (PMI) were single thermocouple/diode and the later Wavetek were dual along with the subsequent Gigatronics and I think the HP's if I recall offhand.? ?
From what IMSAI Guy noted with the Wavetek/Gigatronic..., you can't find the diodes, then you'd have to calibrate and know how to program the EPROM.?
Then again, where there is a will there is a way.?
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Hi Tobias, Do you have any more information on the substitute 8481A you are developing?
Di you make something that worked?
Would really appreciate any reply to explaining where you got to and if it is possible to make a substitute part?
Yours sincerely Jeff ZL4AI
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Francesco
Dave McGuire
jafinch78 .