[aprssig] 434 MHz tracking

Stephen H. Smith wa8lmf2 at aol.com
Mon Aug 6 00:54:22 EDT 2007


Andrew Rich wrote:
> Um the glider was at 8000 feet and i was on the ground.
>  
> Mind you when I drove it, i got 1.9 km's out of it.
>  
>
>     -----Original Message-----
>     *From:* Stephen H. Smith [mailto:wa8lmf2_ at _aol.com]
>     *Sent:* Monday, 6 August 2007 11:09 AM
>     *To:* vk4tec_ at _people.net.au; TAPR APRS Mailing List
>     *Cc:* ozaprs
>     *Subject:* Re: [aprssig] 434 MHz tracking
>
>>
>
>     But how fast were you moving?    In what kind of terrain.   Over
>     what distance?
>
>     1200 baud is much more tolerant of mobile flutter, fading and
>     multipath from moving vehicles than higher data rates,  because
>     it's individual symbols are much longer.     The differences
>     between even 1200 and 9600 on a Kenwood D700 in motion are quite
>     dramatic.  
>

No wonder it worked!  That's "cheating" - a pure line-of-sight 
minimum-loss reflection-free path.   Try it from a terrestrial mobile to 
a base station, especially in a mountainous area or a built-up urban 
area with lots of reflections from buildings, bridges, etc.


--

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      14400    [Think bottom of the 2M band]
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