Meteor Shower, Aurora, Sporadic E Detection using Radio Signal Reflection
by Andy Smith G7IZU

Also as featured in Short Wave Magazine May 2004 (p55).
Some of the site has changed or evolved since the article was published.
 
 
Above: 24 hour FFT plot of the Quadrantids shower Jan 2004.

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Introduction
The radio detection of aurora and meteors is made possible at my QTH in Plymouth, UK by listening to the carriers of distant  Band 1 TV stations. The frequencies I've chosen are 48.250MHz (European TV channel "E2") and 59.258 MHz (channel R2-6p). 

I use DL4YHF's excellent and dead cool Spectrum Laboratory v2.5b6 fed from the audio output of two Icom PCR-1000s in USB mode, which are tuned to zero-beat frequencies of 48.249485 and 59.258330 MHz. The antenna is a dipole, in the loft, tuned to approx 50MHz, with a 9dB wideband dual-output amplifier. Any other frequencies that gives good returns at your location will also do just as well. See the links below for various TV  frequency lists. More detail about the setup can be found here [ How-to setup a Radio Meteor Obs. Station]

Several European TV stations are present on this frequency that cannot be received by ground wave propagation. Any other mode of propagation that bounces the signal in my direction is detectable, such as sporadic E, meteor reflection, auroral reflection and (maybe possibly?) reflection from high-flying aircraft or even spacecraft. I've seen signals that appear to be the later, though proving that theory is difficult! Doppler shifts of a few tens of hertz, as caused by aircraft, have been well observed by others and myself by monitoring HF broadcast carriers, but I'm not sure about the satellites. There may be other reasons for fast changing carriers sweeping through the detection range...

The image above is a very good example of an auroral signal. It was recorded on 31st Oct 2003 between 0010 and 0110 GMT, during the second night of big aurora over the UK in 2 days. Visible in the sky over Plymouth were various red glows and an arc of white stretching overhead. The signal is spread out due to the rapid Doppler shift caused by the charged particles in the auroral curtain rapidly moving. Also, several TV carriers which are a few hundred hertz apart are being reflected simultaneously, making the Doppler effect appear bigger than it really is.