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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