Re: Rain or sporadic Es

On Sat, 15 Nov 2003 09:09:02 -0000, "GM4KGK"
<[EMAIL PROTECTED]> wrote:

>It's a phenomenon known as Anaprop (Anomalous Propagation).
>Decent software modelling can usually factor it out. BUT not always!!

Here we usually call it ducting, and temperature inversions.
It can occur at almost any height, but *usually* within 5000 AGL
Aurora can also cause problems but would be much easier to filter out.
Aurora imposes a modulation on the signal where ducting and inversions
don't normally.  Aurora also occurs in the ionosphere while ducting
and inversions are close to the ground, relatively speaking.

When you discover you are receiving high VHF and UHF stations on your
TV set is most likely an inversion or ducting.  

BTW, either can prevent normal reception of nearby stations in some
circumstances.

I've heard stations from several hundred miles out on my mobile rig,
yet could not hear them on the stacked array at 130 feet.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2).  
>
>GM4KGK
>
>"J Tabor" <[EMAIL PROTECTED]> wrote in message
>news:[EMAIL PROTECTED]
>> Hi,
>>
>> Interesting. We see light rain indicated on radar here quite often. Been
>> wondering what might cause such, just had not investigated.
>>
>> Regards,
>> Jim - ku5s
>> --
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>> Sorry for any inconvenience.
>>
>>
>