[time-nuts] AN/URQ-10A frequency standard

[paul swed]

I looked and must have hit the same site you did for the sulzer. Yes I
expect a lonnnng warmup. I used them in the navy and we never let them go
cold. circa 1973-1979. Took them to the cal lab on battery etc. I thought
maybe I would have a manual I don't.
You are lucky to get one. Great reference. I do have two model 5a sulzers.
I actually use one to generate the lab frequencies for "stuff". I really
should put it back together which I can do and just create a more modern
divider. That would consume less power and be equally clean also take less
space. 1 RU.
Regards
Paul
WB8TSL


On Sat, Apr 27, 2013 at 12:21 PM, Gregory Muir <engineering at mt.net> wrote:

> Thank you for you replies Dave and Paul!
>
> Well, patience won out and I left the unit on for a considerably longer
> time.  The inner oven meter indication then started to come up off of zero
> after nearly seven hours.  Not knowing the thermal mass it has to heat I
> guess I assumed that it would have a slightly quicker response time.  My
> ignorance...
>
> This morning I checked the unit again and the inner oven indication is
> slightly lower than where it should be in the red "OK" region on the meter
> meaning that the heater is still delivering a little more than normal heat
> and the 5 MHz frequency, which started out at ~+33 Hz cold, is now at -1.2
> Hz and holding steady telling me that the heat delivered has overshot its
> normal operating point.  Granted I have not let the crystal assembly soak
> for any considerable time but my mind is thinking about a possible bias in
> the heater control circuit by a leaky passive component or transistor
> causing it to remain on a little more than necessary. But, again, I will be
> patient and watch its progress over the upcoming days.
>
> I pulled out a Sulzer 5A manual and took a closer look at the schematic.
>  From what I observed in the URQ-10 circuitry that is external to the FE-10
> oscillator itself, the power supply and frequency handling portions appear
> to come close to nearly a carbon copy of the older Sulzer unit.  The non-A
> version URQ-10 design is considerably different and somewhat more complex.
>
> And if anyone out there comes across an "A" version manual or has one in
> their possession, I would be willing to compensate them for a photocopy.
>
> Regards,
>
> Greg
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