(meteorobs) What would cause this?

[James Beauchamp]

Yep.  i got them all the time when the AF Space Radar transmitter in Kickapoo was up.  
The initial sweep is a consequence of the math and physics producing a changing frequency component.  Every meteor I detected, with the exception of a very few with a velocity vector along the iso-distance line had these head echos.  

 


     On Saturday, June 27, 2015 11:33 AM, CheekyGeek <cheekygeek at gmail.com> wrote:
   

 Source:http://www.amsmeteors.org/radio/ams203.txt"Very infrequently, the rapidly descending tonal pitch
"whistle" or "whoop" of a meteor head echo can be heard.  This is
caused by the compressed and rapidly expanding ionization around
the meteor head itself reflecting doppler shifted radio waves as
the meteor descends through the atmosphere.  Occasionally, the
meteor head echo will be accompanied by a loud underdense "ping" or
overdense "bong" as the meteor head reaches the first fresnel zone 
and causes a specular reflection as well as a meteor head
reflection.  The first fresnel zone is, roughly speaking, the
primary point at which the meteor trail meets the requirements of
forward-scatter geometry for a particular system.  Those
participants desiring further explanations should consult the lists
in the appendices."
Curious where you are located and the time that this occurred. (Just wondering if it is possibly related the Texas Panhandle event mentioned in another thread.)Respectfully,Darren AddyAlda, NE
On Sat, Jun 27, 2015 at 9:25 AM, Michael Boschat <andromed at dal.ca> wrote:

Hi:
Listening to meteors on 77.251 MHz  - Ch. 5  TV analogue.  picking up good rates on this frequency last few weeks.
anyway, a minute ago I heard a "falling bomb whistle" like  sound, it made a curve on the Spectrum lab plot...
any ideas what would have caused it?

Clear skies
----------
Michael Boschat
Halifax Center - Royal Astronomical Society of Canada 
Astronomy page:  http://www.chebucto.ns.ca/~aa063


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