The images below represent a part of the audio spectrum (typically 800 to 1200Hz) taken from the audio outputs of radio receivers tuned to 143.050MHz (in "upper side-band" mode). On this frequency is a very powerful satellite detection radar, which is located in eastern France, close to Geneva, operated by Onera. More information on how the system works can be found here. Click on the images for super-sized live images.
 

LIVE: NLO - SIDMOUTH, EAST DEVON 143.050 MHz

LIVE: ANDY SMITH - TAVISTOCK, WEST DEVON 143.050 MHz

Click here for full-sized image

Click here for full-sized image

 IMAGES ARE UPDATED ONCE PER MINUTE (WHEN OPERATIONAL). THE SIDMOUTH SITE IS BETTER PLACED THAN WEST DEVON
TO RECEIVE SIGNALS FROM THE TRANSMITTER IN FRANCE, SO MANY MORE METEORS WILL BE SEEN IN IT'S IMAGES.

PLEASE NOTE THAT THESE IMAGES ARE NOT SYNCHRONISED
AND MAY BE ADRIFT BY UPTO A COUPLE OF MINUTES.
THE PAGE WILL SELF-REFRESH, SO NO NEED TO RELOAD IT.


When a meteor enters the atmosphere at a location somewhere between the transmitter and receiver at 80-110km altitude, the meteor's ionized head and/or trail reflects the radio signal for a brief moment, or sometimes for several minutes. 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. Instead it is the sound from the signal of the satellite radar reflected in the plasma (super-heated and electrically charged air molecules) found in the meteor trail.
 
The images are updated once per minute. Time flows from right to left and shows approximately the last 2.5 minutes of reception. The different colours and height of the signal represent the strength of the received signals in the vertical scale.
 


THE MCCLEAN DOME AT NLO


INSIDE THE MCCLEAN DOME RADIO-METEOR SHACK

The location of the Sidmouth site means that it sometimes receives reflected signals from high-altitude aircraft over the English Channel and northern France. These reflections appear as long lines, very slowly descending in frequency. We also see reflections from the moon and from large low orbiting satellites, such as the International Space Station. Please see the Powerpoint presentation (link at bottom of this page) which was made to explain the system to visitors of the NLO.

The Norman Lockyer Observatory is located at Sidmouth, Devon, UK.

Links:
Norman Lockyer Observatory Homepage | Meteor Detection Homepage | Meteor Live View

G7IZU RRD Website (live meteor detection page)

Download a Powerpoint presentation  - how the system works at NLO (requires at least a Microsoft Powerpoint 2007 viewer)
 


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