"I just tried the radio trick and found a digital radio was worthless but an analog AM Radio tuned to triple the EWS theremin frequency (286 kHz) 858 kHz works good." - Touchless
Thats real interesting, T ..
I have never played with AM radios for theremins - (not at all surprised DAB radio never worked ;-) - I never bothered with AM radios because I feared results would be untrustworthy, unless a real simple radio was used (was worried about the effects of the radios LO and getting spurios audio as a result of heterodyning with this).
But I am surprised that 858kHz (f*3) worked - I wouldnt have expected there to be enough 3rd harmonics on the antenna waveform.. Kind of worrying from a RFI perspective - I wonder how high the harmonics go and what strength they are..
When I have played with EW oscillators I have always observed really clean sine waves on the antennas except when the oscillators are close to lock.
I suppose the EW is better suited to this kind of "preview" as its oscillators are simply coupled to the mixer - I wonder if it works so well when the signals are buffered (as with Thierrys ESP add on) or other theremins with buffered oscillators, and / or how much of the reference signal is coming from the antenna vs how much is being directly radiated from the board..
Real interesting though - I should knock a simple tuned circuit "radio" together and give it a try -
Fred.