I've had a quick scan-through but I may have missed mention of Daryl Hock's FM to AM adapter. I thought I'd invented this myself but, as usual, no...
If I understand Daryl's converter correctly, it senses where the AM set is tuned to by picking up the local oscillator. It then uses this information to i. program an AM modulator to where the radio is tuned and ii. tunes an FM receiver by mapping the AM dial onto the FM band.
The result is that the FM band can be tuned using the AM radio's tuning knob!
The downside is the LO pick-up required, and the need to totally exclude all AM stations which means the radio needs a screened aerial connection.
I've no vested interest in Daryl's operation, by the way. In fact I'm a little peeved that he thought of the idea first!
