Hi,
Posted the following about 90 minutes ago, after the
radio had been ON for about 90 minutes at that time.
Sitting here now watching the accuracy of the Orion sub
rcvr, using the method George, W5YR described earlier
today. At turn on, the indicated inaccuracy was about
-17 Hz, as the rig warmed, it drifted upwards reaching to
about + 20 Hz. Now after about 90 minutes, the reading
is 1027.0, or 27 Hz high. Am going to let this run on
for a few hours.
For the last hour+, the indicated MixW signal is at 1026.5 Hz.
The rig is set to LSB, and the tuning reads 10.001.000, or
1 kHz above WWVH.
So, I take it via George's method, my readout is 26.5 Hz too
high.
The Orion's two receivers are coherent in that a single frequency
reference is used. It is a temperature-compensated crystal
oscillator (TCXO) that drives both the sub receiver's phase-
locked loop (PLL) and the main receiver's direct digital
synthesis (DDS) LO.
Presumably then, both rcvr's indicated frequency readout's
are high by this same amount. Of course, by ear, when I
return the rcvr mode to AM, I can tell no change in the signal
whatsoever with the RIT moved + or - 20 or 30 Hz.
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