Nigel
The strategy you propose may not work in a transmitter using two stages (or more) of frequency multiplication.
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Here is the problem. If the 7.05MHz oscillator is replaced by a 28.2 MHz oscillator, the buffer stage output tuned circuit will not be able to be resonated at that frequency. Therefore the output voltage from the buffer stage will be too low to properly drive the following stages of the amplifier chain.
Stu
Stu, thanks for pointing that out. My zero experience level with these older tube rigs really shows. I assumed only one buffer/multiplier stage on an odd order harmonic.
Possibly another approach would be a divide by 4 using 2 flip flops as a DDS buffer, that would both square it up and provide the correct dial reading. Just a thought. Good luck with it Don.
73s Nigel