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[aprssig] APRS on all Radios!!!!

Scott Miller scott at opentrac.org
Sun Aug 17 16:57:34 UTC 2008


Please, can't we just have a fixed-length binary message?  Start using 
varicode (or any Huffman code) and you've got to worry about designing 
for the worst case data.  Callsigns don't have the sort of letter 
distribution you see in natural language.

Stop thinking in terms of text strings, and think about data structures.

Scott
N1VG

Bob Bruninga wrote:
>> In fact, we could make it by-directional and 
>> be full APRS on all voice repeaters.!...
>> Could it simply be PSK-31 encoded? [subaudibly]
> 
> Using existing PSK31 and some clever translations for optimal varicode characters, the callsigns would be about 36 bits and a position to the nearest 6 feet on the globe would take about 64 bits.  CSE/SPD would take 24 bits for a minimum length of about 124 bits or about 4 seconds.  This is about the same average Packet throughput on the APRS channel!
> 
> Interesting.
> Bob, WB4APR





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