Zero beating a signal with any rig having a sidetone (they alldo these days)
is quite easy. Adjust the pitch of the received signal until it matches the
sidetone. Voila! zero beat!
Yep. And if the sidetone frequency is truly equal to the CW transmit
offset from receive frequency zero beat (that is zero beat with the BFO,
not with the sidetone), then your transmitted signal will be zero beat
with the received signal you have zero beat with the sidetone.
If the sidetone is a good clean sinusoidal tone there is little chance
for error. If the sidetone is a harmonic rich waveform, it may be more
difficult to be sure you have zero beat to the fundamental instead of
some harmonic of the sidetone.
In the Ten-Tec radios I have used both of these conditions are met. The
CW TX and LSB RX (which is used for CW RX too) BFO frequencies must be
adjusted properly for this to be the case.
One way to accomplish the above, would be to have two complete BFOs,
(versus one that is frequency switched as in the Omni VI) and use the
audio beat between those two BFOs as the sidetone generator. By doing
that the first condition would always be met, if there is no VFO shift
between TX and RX. I suspect that some radio must have used this
technique. Anyone happen to know a rig that does this?
DE N6KB
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