[time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Tue Dec 2 04:53:15 EST 2014

On 2 Dec 2014 03:10, "wb6dgn_tom at att.net[hp_agilent_equipment]" <
hp_agilent_equipment at yahoogroups.com> wrote:
> Isn't the 10811 a "double oven" oscillator (an oven within an oven)?  I
also believe it has anticipator circuitry to predict changes based on
environmental parameters.  Or...am I confusing this with another oscillator?


Has a data sheet.  I believe that there are variants of the 10811A that are
double oven, but not all are.

The fan is not blowing directly onto the oscillator,  as they are on
opposite sides of the case. But they are both at the rear and given the
instrument is only half the width of a 19" rack, maybe it is too close.

I have not checked this myself,  but someone said that the 5342A pre-dates
the 10811A, so if purchased a 5342A new with the high stability
oscillator,  one would get another oscillator with a poorer specification.

The  5342A/10811A combination is one of those things one would have to
test, rather than guess. It would need some careful thought about how to do
a worthwhile experiment.

Anyway, as far as I am concerned,  it is certainly worth while fitting the
10811A, as even without any equipment other than my eyes, I can see the
last few digits are not constantly changing every second or so.  There's a
dramatic improvement in short term stability.  I would guess it has  2-3
orders of magnitude better short term stability, based just at looking at
the display.  Actual measurements would quantify the improvement.

If I can get 100-1000x better performance,  for an upgrade that costs less
than 25% of the instrument, that is worthwhile to me. Waiting 6 or so
minutes to get a dramatic improvement in performance is not a big deal.
Keeping it plugged in 24/7, for a bit more performance, is not worthwhile
to me, but others may feel otherwise.


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