[TenTec] Some Observations on Orion Stability/Calibration

[k6se at juno.com]

In my last post, I wrote, "Someone said that WWV frequency accuracy
depends on propagation delay, which I agree about....".  Thinking about
that, I now have to disagree.

Propagation delay affects accuracy of WWV's time signals.  The delay can
accurately be calculated for ground wave signals such as WWVB on LF, and
can be estimated for HF WWV sky wave propagation.  However, propagation
delay has nothing to do with the received accuracy of WWV's carrier
frequency.

The only thing that would affect the frequency accuracy of WWV's HF
signals would be Doppler.  The only thing I can think of that would cause
the Doppler effect would a shifting up or down in height of the
ionosphere.

The ionosphere most certainly would not be constantly shifting either up
or down in height at any great speed, but it could possibly be rapidly
shifting back and forth between a given height during any short period of
time.  This would be heard on the signal's carrier as a slight "buzzsaw"
effect, which I've never heard on WWV.  So if it does occur, it must be
extremely slight and therefore negligible to us that are calibrating our
TCXOs.

If anyone knows of another way that Doppler effect (or otherwise) that
can influence the received carrier frequency of WWV, please let me know.

73, de Earl, K6SE