* Astronomy

Blobrana · L

RE: Meteor scatter propagation

Blobrana · L

ANDORRA, C3. Chris, PA2CHR is QRV as C37MS until June 7. He is active on 2 meters looking for meteor scatter and sporadic-E propagation on 144.358 MHz using FSK and 144.318 MHz using SSB, respectively. QSL to home call.
Read more

Blobrana · L

TV-DX: Meteor-Scatter on VHF R1

Click to Play | View Details

Blobrana · L

Meteor scatter occurs when a signal bounces off a meteor's ionised trail.

When a meteor strikes earth's atmosphere, a cylindrical region of free electrons is formed at the height of the E layer. This slender, ionised column is relatively long, and when first formed is sufficiently dense to reflect and scatter television and radio signals, generally observable from 25 MHz upwards through UHF TV, back to earth. Consequently an incident television or radio signal is capable of being reflected up to distances approaching that of conventional Sporadic E propagation, typically about 1500 km. A signal reflected by such meteor ionisation can vary in duration from fractions of a second up to several minutes for intensely ionised trails. The events are classified as overdense and underdense, depending on the electron line-density (related to used frequency) of the trail plasma. The signal from overdense trail has a longer signal decay associated with fading and is a physically a reflection from the ionised cylinder surface, while an underdense trail gives a signals of short duration, which rises fast and decays exponentially and is scatter from individual electrons inside the trail.
Read more