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Re: (meteorobs) radio detection

Yes they produce radio waves. They produce electromagnetic waves in the
VLF and ELF (very and extremely low frequency) range around 10 to 60 Hz
(that's Hz not KHz). This low frequency radio energy has been know to
induce vibrations in metal objects (like your glasses frames) producing
sound waves (very rare).
It takes a very large meteor to produce a recordable event but the
effect is very common and well recorded during space shuttle reentries.
Every space shuttle reentry produces an easy to record event. Sky and
Telescope and Scientific American have both run artcles with
instructions on how to receive the signals. The easiest way is to simply
take a very long wire 10ft or more, and connect it directly to the
microphone jack of a tape recorder. No radio receiver is required. Some
people use large ferrite bar antennas with long wire wraps but that can
overload a microphone input. Then later play the tape into your computer
via the sound board and keep it as a WAV file, then analyze the wav file
with a sound editing program like Cooledit (there are lots of freeware
sound programs out there). Cooledit will do a FFT (fast fournier
transform, hope I spelled that right) and you have the frequency of the
transmission... easy. You could set up a wire and tape recorder during a
meteor shower and if you see a REALLY big one mark the time and input it
into your computer later.
Dale

Lew Gramer wrote:
> 
> Sri, I know little about radiometeors, but I do know they are most commonly
> detected because the ionized trail of particles they leave in our atmosphere
> can reflect radio ground signals back to the ground. The frequencies most
> commonly monitored for this reflection by amateurs are in the 40 to 150 MHz
> range (source: George Zay), which includes TV and FM bands.
> 
> As to whether the meteor entry burns themselves generate radio waves, or
> whether the "electrophonics" produced by the ion trail's interaction with
> earth's magnetic field is real or not, I couldn't say.
> 
> Can someone with more experience and knowledge answer Sri's question?
> 
> Clear (and static-free) skies,
> Lew Gramer

-- 
Dale Ireland 47.7N 122.7W
Astronomy Web Page, http://www.drdale.com
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