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RE: HF Walkie Talkie



The inverse square law only applies to line-of-sight propagation.  Over real terrain, the path loss typically varies as 1/r^3 or 1/r^4.

Al N1AL


> -----Original Message-----
> From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org]On
> Behalf Of Robert Bruninga
> Sent: Monday, December 20, 2004 6:24 AM
> To: amsat-bb@amsat.org
> Subject: [amsat-bb] HF Walkie Talkie
> 
> 
> HF Walkie Talkies?
>  
> In this months QST the old WWII walkie talkie was discussed
> and it was a 20 milliwatt transmitter good for up to one
> mile.   Doing the 1/r^2 equation means that 5 watts would
> equate to about 16 miles.
> 
> And the frequency was 80 meters with a 3 foot whip.
> 
> Since our entire HT experience is with 2m and up, I wonder
> what the real world experience would be like with HF HT's?
> (staying with handheld antennas).  We all know that you
> can work the world with 5W on HF skywave, but I am only
> interested here in ground-wave and line of sight.  Just curious, 
> never thought much about it before.
> 
> RX noise level of course is very high... but what about 
> propogation through the woods?  etc...  We sorta know
> about CB HT's too, but what about down there at 
> 7 MHz?
> 
> On topic since most of the HF bands are satellite bands too
> and can be used for Satellite uplinks...
> 
> Bob
> ----
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