Summary

TV, radio, and other signals are reflected via meteor ionization trails.

A 10 element elevation over azimuth yagi antenna, plus an Icom R8500 receiver form the basis of this instrument.

Signals from the 216.98 MHz NAVSPASUR (Naval Space Surveillence Radar) in Jordan Lake, Alabama can be received via meteor reflections. NORAD, the North American Air Defense Command, uses this and other similar radars to refine the orbit information on several thousand satellites and pieces of space debris.

This is a bistatic radar, which means a constant signal is broadcast upward in a continuous fan beam. Anything that hits this imaginary fence in space, reflects some of the radar energy back to several receivng sites throughout the US. By precision time and frequency analysis the orbit of a satellite may be determined.

Meteors will also hit the "fence" and reflect the signal back to our receiver. This allows us to graph the intensity of meteor showers hour by hour for comparison to data from prior years. Doppler shifts in the signal give a measure of velocity and relative size of the meteors via signal intensity changes.

Meteor scatter also propagates TV and FM radio stations from up to 1200 miles away at times. Brief bursts of signal lasting typically one or two seconds up to as much as 30 seconds often occur during any one of several dozen periodic showers each year. 

To listen to these TV or FM signals reflected from the meteor's ionization trail, tune to an otherwise blank channel. TV channels 2 thru 6, and the FM radio band are prime frequencies on which to listen. During times of peak meteor activity stations will pop in for a few seconds at random times.

Click image for an audio recording of a meteor reflected signal ( 124 kb).

The showers are named after the constellation which each shower appears to radiate from. The Leonids, each year around November 18th, appear to come from the constellation Leo. In reality Earth is passing through the remnants of a comet's orbit through the inner solar system. Bits of rock and dust trail behind the comet as a portion of its icy core melts away with each successive orbit. These bits of rock are swept up by the Earth causing meteor showers.

There are also some subtle Very Low Frequency (VLF) effects observed from time to time. See our VLF page for details.

Tons of meteors enter the Earth's atmosphere each day unnoticed. Most are barely dust grain size and don't make visible streaks, but can reflect radio signals in the 20 to 400 MHz frequency range.

      Power Point presentation on using the 217MHz NAVSPASUR ( 1.6 MB ).
      American Meteor Society

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