Found on the AM Forum.

Occasionally in ham radio, there a few things that turn  up now and 
again that make my jaw drop- this is one of them.

Http://mjrainey.googlepages.com/elsilbo

"This double-sideband (DSB) radiotelephone transmitter is powered 
entirely by the instantaneous (not stored) energy produced in the 
operator's voice. The RF output power in my prototype falls within the 
range of 5 to 15mW. The circuit is essentially a high-level DSB 
modulator/crystal-controlled RF oscillator."

Seems the louder you shout , the further you get.

73s Brian GM4DIJ
-- 
Brian Howie

On 4 Nov, 08:42, Brian Howie  wrote:
> Found on the AM Forum.
>
> Occasionally in ham radio, there a few things that turn  up now and
> again that make my jaw drop- this is one of them.
>
> Http://mjrainey.googlepages.com/elsilbo
>
> "This double-sideband (DSB) radiotelephone transmitter is powered
> entirely by the instantaneous (not stored) energy produced in the
> operator's voice. The RF output power in my prototype falls within the
> range of 5 to 15mW. The circuit is essentially a high-level DSB
> modulator/crystal-controlled RF oscillator."
>
> Seems the louder you shout , the further you get.
>
> 73s Brian GM4DIJ
> --
> Brian Howie

I seem to remember some Scottish Chap did the same thing with just a
couple of wires back in 1877.

that guy's just invented the AM transmitter (without the audio amp
stage). But fair play to him, it is amazing how far you can get with a
few milliwatts - I would imagine it takes quite a bit of patience
though (and a loud hailer)