Re: HP Power Sensor wanted

Chris Bartram G4DGU

As they were needed for my former work (apologies for the bad language!) I have a number of power meters complete with sensors to 40GHz. While for historical reasons I don't lend instruments, I'd be quite happy to 'calibrate' anyone's home-made sensor.

While I have working a 8485 and a 8482, I also have a damaged 8481 which suffered a gross overload due to my utter stupidity. Although a repair would be possible, I can't now justify the cost of the replacement thermal sensor module.

I have somewhere seen a design for a diode detector module designed as effectively a drop-in replacement for the 8481 electronics (albeit with out the accuracy!). Does anybody have a reference?


Chris G4DGU

On 25/09/2020 08:39, geoffrey pike via wrote:
I have used a AD8317 in a non working HP435B and without changing its original state, just use the meter.
From my notes(i actually have them), its performance at 10 GHz (AD8317 spect to 8GHz) shows it
reads about 20 dB low the real value and fairly good to 8GHz. Scaling on the meter is in my case -5dBm FSD and -30dBm mid scale with 55dB range.
The AD8317 does have a -ve output slope, anyway for about a tenner you have a meter that you can abuse and not worry about the thermistor head

On Thursday, 24 September 2020, 21:25:07 BST, Paul Randall G3NJV <paulfrandall@...> wrote:

Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV

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