Forward scatter
Forward scatter is a method of detecting meteors by listening for distant radio signals briefly reflected by meteor trails.
Forward scatter is a way to detect meteors using radio. A transmitter sends out a continuous signal, often a television or radar station hundreds of kilometres away whose waves normally cannot reach a receiver over the horizon. When a meteor passes in the right place, its ionised trail briefly reflects the signal down to the receiver, which hears a short 'ping' or tone.
Amateur radio enthusiasts and schools use this method to count meteors in daylight, through clouds and during the day, which visual observers cannot do. Several daytime meteor showers, such as the Arietids in June, were discovered or studied by radio, because their radiants are too close to the Sun to see.
In Europe, the French GRAVES space surveillance radar is often used as a transmitter for forward scatter observations. A simple receiver, an aerial and free software are enough to start. Counting pings over a night shows the rise in meteor rates towards dawn.
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Level: Expert Advanced