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

[Gregory Muir]

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