Looking back on my emails I see some correspondence from Michael Rainey AA1TJ about a sound powered CW TX he built. I think Michael's TX involved converting sound from his voice into CW RF. I have seen other circuits that convert the action of pressing the Morse key into RF. In theory, this would also work with speech. Of course, physics dictates that low milliwatts only can be achieved.
If you know of ideas, please let me know.
A few people are currently experimenting with sound powered RF transmitters, generating the DC power to run a microwatt level oscillator from the human voice or morse key activation. There have been a few such ideas published. What appeals to me is a sound powered TX coupled with a crystal set RX. Such a system might get a mile or two as long as the station at the far end was running a few watts of AM or MCW. This would be the ultimate in QRPp!
