[time-nuts] Ovenaire oscillator

Joseph Gray jgray at zianet.com
Tue Apr 12 07:22:29 UTC 2011


I have an Ovenaire 10 MHz oscillator that was pulled from some junked
equipment. Just for fun, I put it on the bench and hooked it up to a
variable power supply. Watching the frequency output with a counter, I
powered it up.

According to the schematic, the onboard voltage regulator circuit
produces 15 VDC into the OCXO. The fine frequency adjust is done by a
trim pot on the board (I haven't touched that yet). I set the DC
supply to 18 V to allow for some losses through the onboard regulator
circuit. At startup, the Ovenaire draws about 250 mA. As the oven
heats up, the current slowly drops. After less than ten minutes, it is
at 170 mA and still falling. I'll let things run for a while to
stabilize. At the moment, the Ovenaire is a few Hz low.

After first powering the Ovenaire on, I wanted to see how it would
react to a lowered supply voltage. To my surprise, it continued to put
out near 10 MHz as I dropped the supply voltage all the way down to 9
V into the onboard regulator. Remember, the schematic showed 15 V into
the OCXO.

After messing around with things as they are for a bit, I'll have to
hook up the T.I. counter and the GPIB for comparison against my
Z3801A. I know I'm still a time novice, but this stuff can be
interesting :-)

Joe Gray
W5JG



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