[aprssig] Help with Interfacing a GPSto Kantronics KPC-3

Stephen H. Smith wa8lmf2 at aol.com
Wed Jan 3 17:11:18 CST 2007

bruninga at usna.edu wrote:
>> The transmitting of raw NMEA strings over the air... 
>> ... is highly discouraged in California.  Raw NMEA 
>> ... occupy up to TEN times more air time than the 
>> most compact encoding format for APRS (Mic-E).
> A little caution and explanation with that advice...
> 1) True, it is 10 times longer, but when you include the packet
> overhead this is more like only a factor of 2 longer.
> 2) The KPC-3+ TNC tracker that sends raw NMEA can actually
> produce less QRM, because it can be set to PROPORTIONAL PATHING.

This accomplishes nothing in Southern California where all the 
digipeaters enforce SINGLE HOP no matter what path is set into the 
tracker.   All you are doing is transmitting longer packets that:

1)  Occupy more air time

2)  Are much more likely to get trashed due to congestion on the 
saturated channel here. 


Stephen H. Smith    wa8lmf (at) aol.com
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