[time-nuts] Problem with HP 83623A 20 GHz sweep generator stepping up/down 100 Hz when not wanted.

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Thu Dec 22 07:39:27 EST 2016

On 22 December 2016 at 03:17, paul swed <paulswedb at gmail.com> wrote:

> Dave Congratulations on 10 Ghz SSB.

This was not a QSO at all. It was simply a one way transmission from a
signal generator at my end to a receiver at his end. No QSO was attempted.

> Now to your question. I will fully believe you are seeing normal behavior
> of the generators. Even if its dithering 100 Hz thats pretty amazing. Sweep
> gens simply are not stable enough for narrow work like you are trying.
> Now I am sure comments will prove me totally wrong.

But I find it a bit odd that HP would have a 1 Hz software option on this
instrument, if the instrument jumped up/down 100 Hz.

Now I don't yet have the 1 Hz option programmed in, and it might well
change the behavior completely, but I'd still like to find a way, if one
exists, of checking this with the equipment I have.

The signal generator is no longer supported, but I could try my luck seeing
if there are any known problems with this unit, or firmware upgrades
available - currently revision 29, May 1991.

> But I don't think so. (Have been on 10G SSB over the years also. Only 60
> watts plus. Nothing fancy. ;-)  )
> Regards
> Paul

60 W is clearly some setup. I also know a lot of people run portable stuff
on 10 GHz, where achieving frequency stability is more of a challenge,
although less so with GPS. But this is a laboratory instrument, from a
reputable manufacturer. I personally would not expected this behavior. I
actually purchased this very cheaply (£650 GBP, which would have been about
$900 at the time), but they are not cheap to buy now.


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