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Old 06-01-2016, 07:20 AM   #6
NN5I
Carl, nn5i
 
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Location: Tallahassee, FL
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It is certainly sensing RF. Lightning detectors have been around for a long time.

They detect RF and distinguish (or attempt to distinguish) lightning-generated RF by its risetime and its frequency distribution (which are not, by the way, independent variables). They estimate distance mostly by amplitude, so one would expect anything that reduces the signal strength (such as the metal body of a trailer or motor home) to cause them to estimate the distance as greater than it is. Other effects (such as the difference in polarization of the RF depending on whether it's cloud-to-cloud or cloud-to-ground) may cause the detector to think the lightning is closer than it is.

In order to indicate the direction of the lightning from the detector, the detector must use some configuration of multiple antennas. With only one antenna, it can estimate distance but not direction.

The first lightning detector (invented, if I remember correctly, late in the 19th century) was also the first radio receiver.
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