[VHFcontesting] Newbie questions about propagation...

[David Olean]

Dust off your key and microwave set because the band is open!  Inversions 
tend to setup on higher frequencies before lower frequencies oftentimes. 
Other times the microwaves are not propagated as far as lower frequencies, 
but if the NWS is complaining, it means that 5 and 10 Ghz are most likely 
really hot!

Dave K1WHS


----- Original Message ----- 
From: "Les Rayburn" <les at highnoonfilm.com>
To: <vhf at w6yx.stanford.edu>; "VHF Contesting Reflector" 
<vhfcontesting at contesting.com>
Sent: Thursday, May 22, 2008 3:10 PM
Subject: [VHFcontesting] Newbie questions about propagation...


>I hope that you'll all humor some more "newbie" questions. Like many, I 
>monitor the APRS map to determine the likelihood of enhanced propagation. 
>It doesn't take long
> to figure out that it can be misleading. This morning, most of the Gulf 
> Coast was covered in "red", along with Central Alabama where I am located. 
> My receiver told a different story...
>
> Other than W5RCI, in Marks, Mississippi the band was quite. Noisy, but no 
> signals to speak of.
>
> Then this morning, I got this e-mail from the National Weather Service. I 
> wonder what type of propagation is their radar seeing? Tropo? Should I get 
> into the habit of checking their radar looking for these false returns?
>
> 73,
>
> Les Rayburn, N1LF
> EM63nf
> 121 Mayfair Park
> Maylene, AL 35114
>
>
> ...FALSE ECHOES ON THE RADAR THIS MORNING...
>
> CENTRAL ALABAMA RESIDENTS MAY WANT TO CARRY AN UMBRELLA TODAY...BUT
> NO NEED TO GET CONCERNED ABOUT THE MORNING RADAR IMAGERY.  AREA
> RADARS ARE SUFFERING FROM A PHENOMENON CALLED ANOMALOUS PROPAGATION
> OR AP.  AP OCCURS FREQUENTLY THIS TIME OF YEAR WHEN AIR WARMS
> SIGNIFICANTLY JUST OFF THE SURFACE TRAPPING THE RADAR BEAM...KIND
> OF LIKE A MIRROR...REFLECTING THE BEAM BACK DOWN TO THE SURFACE.
> IN ESSENCE THE REFLECTIONS SEEN ON RADAR IS THE SURFACE OF THE EARTH
> OR AT LEAST FEATURES ON THE SURFACE. THESE FALSE ECHOES SHOULD
> QUICKLY DISAPPEAR AS SURFACE TEMPERATURES WARM THIS MORNING.  EXPECT
> ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP AFTER 3 PM THIS
> AFTERNOON.
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