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The image below represents
a part of the audio spectrum from the output of the NLO radio receiver which
is tuned to 143.050MHz. On this frequency is a very powerful satellite
radar which is located in eastern France, close to Geneva, operated by Onera. |
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TOP: Norman Lockyer Observatory, Sidmouth, Devon, UK
BOTTOM: Andy Smith, Tavistock, Devon, UK
UPDATED ONCE PER MINUTE (WHEN OPERATIONAL)
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Data plots (G7IZU)
Top graph: meteor counts per hour
Bottom graph: ping durations (secs per hour)
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When a meteor enters the
atmosphere at a location somewhere between the transmitter and receiver at
80-110km altitude, the meteor's ionized trail reflects the radio signal
for a brief moment. The signal appears as quick "ping" of sound from
the receiver which is rapidly descending in frequency, due to the Doppler
effect. It is not the direct sound from the actual meteor. The
image is updated once per minute and time flows from right to left. It
shows approximately the last 2.5 minutes of reception. The different
colours represent the strength of the received signals.
The Norman Lockyer Observatory is located at Sidmouth, Devon, UK.
Links:
NLO Homepage
G7IZU RRD Website (live page)
Download a
Powerpoint presentation
- how the system works
(requires at least a
Microsoft Powerpoint 2007 viewer)
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