Re: A homemade diode power sensor for HP meters
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Please trim everything, after the item number. The rest is your tracking information. Highlight and delete the question mark and everything that follows to give a result like this:
On Sat, Mar 12, 2022 at 6:36 PM Bob Stewart < bob@...> wrote: 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?
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A couple of thoughts on that…
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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.
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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.
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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.
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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.
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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.
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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?
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Michael A. Terrell