Re: CW OPERATION
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On receive it is the BFO which must be offset and NOT the transmit frequency.
When we had separate Tx and RX and the RX had a variable BFO (CR100/B28, CR300, Atalanta and their siblings, AR88 etc and all the old ex-service Boat Anchors). the BFO was set at the centre of the IF, zero beat the incoming signal and then shift the BFO up or down the IF passband for your favourite (or xtal filter) tone. You could also peak the signal if you had an S meter and shift the BFO accordingly.
Same used to be done when listening to SSB where you had to choose the correct injection frequency for USB or LSB.
Some of the old boat anchors had the local oscillator on the high side of the received signal on lower frequencies and on the lower side on higher frequencies than the signal so that when you adjusted the BFO to receive LSB on lower frequencies you would receive the USB on higher frequencies and vice versa as this caused sideband inversion.
This was done for better tracking on lower frequencies and better (how much) stability on the higher frequencies as the local oscillator was lower in frequency than if it was on the high side of the received signal.
On the TX side, usually the TX was switched on "net" which powered the VFO buffers etc but not the pa so that you will hear the TX signal in your receiver, zero beat with the incoming signal you wanted to answer and you will be tuned to his / her frequency.
Memories and regards from an old timer
On Mon, Sep 3, 2018 at 4:28 AM Jim Sheldon <w0eb@...> wrote: