(meteorobs) Negative HF radio meteor reception

[Sam Barricklow]

Thomas,

Due to the lower frequency, the doppler shift is considerably less at  
HF frequencies than at VHF.  Also, to hear a meteor radio echo that is  
not "polluted" by either ground wave or sky wave, your receiver must  
be within the "skip zone" and beyond ground wave distance.  The skip  
zone is where the skywave is passing above your location on its way to  
or from the refraction zone in the ionosphere, and before the signal  
returns to the Earth's surface.

The ideal signal source for HF meteor radio echo work would be a  
shortwave broadcast station that is located over the horizon, too far  
away for you to hear groundwave and too close for ionospheric  
propagation to occur.

Here's a link to a YouTube video on the subject:

http://www.youtube.com/watch?v=xgrxQdRrCRE

A limited amount of information is available at the following website:

http://sci2.esa.int/leonids/leonids99/leolisten.html

WWV in Fort Collins might be useful for you when the MUF (maximum  
usable frequency) is lower than or near the receive frequency,  
especially for the 15 and 20 MHz frequencies.  WWV transmits at 2.5,  
5, 10, 15 and 20 MHz.

Other propagation modes might produce "interference" even when no  
direct ionospheric or groundwave propagation exists, such as  
backscatter or even forward scatter, both of which are mostly produced  
by the ionosphere.  Backscatter from distant mountains or ocean waves  
may also provide signal reflection / refraction at times.   
Tropospheric ducting might occasionally allow propagation, but it is  
more common at VHF and above.

Note that refraction produced by meteor trail ionization will normally  
last longer on HF than on VHF.

Sam Barricklow

On Mar 2, 2012, at 11:54 AM, Thomas Ashcraft wrote:

> I am not aware of any HF radio ( high frequency or decametric  )  
> direct
> emission monitoring of meteors or papers on the subject.

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