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[aprssig] Freq Info for NMEA and other Trackers

Robert Bruninga bruninga at usna.edu
Mon Nov 19 21:27:06 UTC 2007


NOTES for NMEA-GPS or other trackers:

We have tested this method for placing your voice operating
frequency into the beacon text of your NMEA tracker so that you
too can share in the world of two-way human-to-human APRS
communications.

Simply make sure that the first 10 bytes of your BEACON text
includes your voice operating frequency in this format
">FFF.FFFMHz more..." where "more... Can be any additional text.
The leading ">" makes it into an APRS STATUS packet.  This also
works for old D7 and D700's too.  Just put your "FFF.FFFMHz" as
the first 10 bytes of your STATUS text (without the ">").

This places your frequency in a known, parseable format for any
existing and future applications.  For example, the D710 can
then tune your frequency with a single key press (TUNE).  All
authors should consider parsing this location for FREQUENCY info
for all stations.  This is extremely valuable and part of the
ARRL initiative after Katrina, to make sure we had a way of
contacting ALL ham radio operators by prominently displaying
their frequency of operation. . Email address is also handy...

Almost all APRS stations have these attributes:

POSITION  (includes PHG data)
STATUS    (free field, but often email address
FREQUENCY (their operating or contact frquency).

We started adding FREQUENCY as the first 10 bytes of the
POSITION COMMENT or STATUS packet to APRS several years ago.  We
need to make sure all web pages tell people how to enter their
frequency into their APRS packets, and new software knows how to
parse it.  See the APRS Frequency SPEC:

http://www.ew.usna.edu/~bruninga/aprs/freqspec.txt

Bob, WB4APR

> -----Original Message-----
> From: digiowners at yahoogroups.com 
> 
>>> What is the... recommendation for a NMEA tracker
>>> to be compliant with the APRS Freq Spec?... so 
>>> the mobile announces its frequency?
>> 
>> Answer is to set your beacon text to be:
>>   BT >146.520MHz blah blah...
>> 
> 
> Bob, Wb4APR





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