More than just a Ham radio blog.
is an informative, cynical and sometimes humorous look at what is happening in the world of amateur radio.

Monday, 26 October 2009

100 miles by voice powered radio

Michael.J.Rainey AA1TJ is a QRP enthusiast that has built what could be described as the greenest radio transmitter on the planet. His ‘El Silbo’ project is a double-sideband (DSB) transmitter is powered entirely by the energy produced by the operator's voice. He has completed three QSO’s with a best DX of 100 miles using the device, which puts out between 5 to 15mW. The circuit is essentially a high-level DSB modulator/crystal-controlled RF oscillator.

El Silbo apparently takes its name from Silbo, which is a sort of a whistled language that's used on the isle of La Gomera (Canary Islands) to communicate across wide mountain valleys. The best DX is apparently 2 miles, or just over 3km.

Roger G3XBM points out that this sort of thing has been done before with a 1955 article from Time magazine. The item tells how the Army Signal Corps has developed a radio transmitter that needs no energy except electricity generated by the speaker's voice. The inventor, George Bryan managed to transmit 600 feet with a device small enough to fit in a telephone mouthpiece but suggested a range of a mile was possible.

Roger says over at his blog that Michael is also working on a receiver that uses RF harvesting techniques, which if I am correct means taking the received RF from a high-powered broadcast station and using it to drive the amplification stages in an amateur radio receiver.
Maybe it is just me but I feel these ideas may lend themselves to the development of future innovations such as an RF powered watch or as a way to power nano-technology. Just imagine tiny robots powered by RF from a BBC radio one or how about a receiver in your car powered by the noise from the engine. The only limitation is our imagination.

No comments:

Post a Comment