TC stands for Temperature Compensated, NOT Temperature Controlled. So
the oscillator controls should be responding to its environment.
But HF propagation causes short term variations in frequency of about 1
part per million, 20 HZ at 20 MHz WWV so the measurements may not be of
the TCXO but likely are of propagation changes. Frequency measurement
specialists expect it to take a month of averaging HF WWV signals to get
to within that 1 PPM. Hoping to do it in hours just isn't going to
happen.
Only propagation at VLF, like 20 and 60 KHz can allow better frequency
distribution than a PPM, and then its not right if there's an aurora
about like there has been last week.
73, Jerry, K0CQ
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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.
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