Stornoway Radio Meteor Echoes Station

What you can hear and see in this continuous waterfall display (the technical term) are meteor echoes, caused by the reflection of radio waves on the hot ionised air that a meteor leaves behind after it disintegrates while entering Earth’s atmosphere.

The most active daily period is the one that precedes sunrise (GMT time zone), but echoes can be seen and heard at any time of the day, more of them during the meteor showers. As long as the waterfall continues scrolling, there is a possibility of registering a meteor echo. Sometimes, satellites are also detected, and the International Space Station is almost regularly observed.

The signals will appear in the area between 1040 and 1100Hz, marked on the top white band by the big horizontal square bracket. The constant background sound is simply noise, while the meteor echoes will have a more high pitched tone, different from the base one. Furthermore, the longer and more complex an echo is, the longer and more intricate its sound will be.

This kind of meteor observation can be done regardless of the weather or the hour, so it is possible to see and hear meteors during daytime whit a rainy cloudy sky. However, it can be long before an echo appears, or between two of them, so do not expect to see one meteor after another, except during the peaks of the most intense meteor showers (Perseids in August or Geminids in December). In any case, patience is the key.
Going a bit deeper into the subject, as stated at the start, when a meteor enters Earth’s upper atmosphere it disintegrates at an altitude between 80 and 130 km (50 to 80 miles), leaving behind a visible streak of light (which are very easy to spot during meteor showers) and also a trail of hot ionised air that can reflect radio waves. Using the French GRAVES space radar as a source, this stream shows the radio echoes that my equipment is able to capture from far away.

The hardware that makes this possible is:
– a 9 Element Yagi (14.3dBi free space forward gain)
– and an Airspy R2 RTLSDR Dongle
– a normal (even a laptop) computer

For the software part, instead:
– SDRSharp software connected to the SDR, tuned on the frequency of 143.050 MHz
– SpectrumLab software (which is the one you see in the LIVEstream) to refine the signal, to automate the count and to save screenshots of the meteor echoes

The GRAVES (Grand Réseau Adapté à la Veille Spatiale – Large Network Adapted to the Surveillance of Space) is a Radar that enables the French Air Force to track and catalog space debris, as well as observation and listening satellites operating in low earth orbit, at an altitude of between 400 and 1,000 km (250 and 620 miles). The radio waves emitted, however, reflect very well also on hot meteor trails, and even if this receiving station is more than 1500 km (930 miles) away from the signal origin point, and more than 2000 km (1242 miles) away from the impact area of the meteors into our atmosphere, it is possible to see and hear many echoes during the day and night, with continuous 24h/365d receiving possibility.