[Premium-Rx] RACAL 9442 OCXO

[Andrew Holme]

I have one of these in my RACAL 9916 UHF counter and a spare on a 1792 
mounting base.

The 1 MHz STD OUT from the rear of the 9916 counter has -70 dBc sidebands at 
~ 1 KHz offsets.

The spare 9442 sometimes has them (at around -40 dBc) and sometimes not!!! 
I can make them go away (or come back) by momentarily interrupting the 
supply.  It's had plenty of time to warm up and I'm only interrupting it for 
a fraction of a second.

Does the heater work by PWM at around 1 KHz?

Any theories?

TIA