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[aprssig] Project-25 for amateur radio

Robert Bruninga bruninga at usna.edu
Sat Aug 16 01:09:30 UTC 2008


> Bob, there is a low-speed data mode transmitted 
> along with digitized voice on Project 25... 
> at 88.9 bit/s. ... I doubt that it would be very 
> practical to use "APRS over P25," ...

Ah, that means a callsign in one second.

And from a 6 byte callsign you have more than enough information
to place that person in the APRS system with ALL of this very
important information...  And that is almost all you need for
APRS:

1) Call,
2) Date and time heard
3) Location heard (vicinity of that repeater)
4) Voice Frequency he is monitoring (that repeater)
5) ECHOLINK or IRLP node number (of that repeater or nearby)
6) Event, status, situation etc... (of that repeater, right now)

That is a full APRS packet and tells us everything we need to
know for global communications with that person.  All from just
a callsign.  That is why we really need APRS Touchtone, And
Project-P25 and DSTAR, and any other source of on-air
information brought into APRS, so that we can communicate with
all of ham radio operators, not just the 3% that have APRS
radios in their mobiles.

If you want more info on how all this is translated from just a
callsign to everything you need to know on APRS please see the
APRStouctone web page:

www.ew.usna.edu/~bruninga/aprstt.html

Now then, at 88 bits per second (10 bytes per second), we can
get an entire precise GPS position report too in only 2 more
seconds....  Then you have FULL APRS for every 3 seconds his key
is down.  Inncluding symbol etc... (using Mic-E format).

Why aren't we doing this?

Bob, Wb4aPR

> On Fri, Aug 15, 2008 at 3:38 PM, Robert Bruninga 
> <bruninga at usna.edu> wrote:
>> I noticed the QST article on Project 25...
>>
>> I noticed a sentence about simple text transfer....
>> If the radios are capable of digitally exchanging 
>> callsigns, then there is no reason why they cannot 
>> appear on APRS just like DTMF users....
>>
>> See http://www.ew.usna.edu/~bruninga/aprstt.html
>>
>> Bob, WB4APR 





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