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[aprssig] [WOTADB] Frequency Reporting by APRS too

Wes johnston wes at kd4rdb.com
Sat Apr 8 18:41:51 UTC 2006


I've been working with the NWS in Columbia SC.  We are trying to encourage 
the skywarn spotters to use tiny traks on their voice rigs so that their 
positons can be sent out via mic-e on the local repeaters.  On point of 
contention is that the NWS guys need to know what frequency the skywarn 
people are on.  To that end, we are also asking the local repeater owners to 
install TNCs at the repeater sites that will call swap on digipeat.  Then 
they'll just program the TNC callsign to the numeric version of the repeater 
frequency, and the TNC will substitute that frequency mnenomic for the first 
hop in the path.  Then we'll know what frequency they are on.  The only 
problem I see with this, now that I am writing it down is that the 2nd hop 
call substitution will overwrite the frequency name that the repeater's TNC 
put in, right?

Anyway for the time being, they have a pretty neat setup at the NWS CAE. 
They have three 2m rigs each hooked to a speaker and a line input on the PC 
sound cards.  (Yes, there are two sound cards in the PC).  This lets them 
talk to a local repeater, a repeater to the west and a repeater to the 
east... all the while listening for mic-e packets on all three.  We're 
running AGWPE on both sound cards giving us 4 channels of audio to decode 
packets from.  They are also running a d700 in packet mode hooked to AGWPE 
in kiss mode.  Xastir is the aprs program that ties it all together, 
including radar overlays from the ridge radar server.

I guess the point of this email is to say that Bob is right on the money.... 
people using aprs data want to know what frequency they can use to talk to 
all the pretty cars on the map.

I think James Jefferson (of aprsworld ) wrote a pic program that would 
figure out what frequency the d700 radio was on and alter the beacon text 
automatically.  It's a shame the tiny tracks and open trackers don't have a 
way to change the comment fields in the field... as it stands each of the 
devices only has two modes, therefore two shots at a beacon text.  I suppose 
you could programm mode one to say the most popular repeater in your area 
and mode to to say the other repeater you are normally on... but they we 
have to remember to switch modes when we QSY.... bad / incorrect information 
is worse than no info.

Wes



----- Original Message ----- 
From: "Robert Bruninga" <bruninga at usna.edu>
To: <aprssig at lists.tapr.org>
Sent: Saturday, April 08, 2006 10:20 AM
Subject: [aprssig] [WOTADB] Frequency Reporting by APRS too


There is a move afoot by the ARRL to make it
easiler to locate Hams' operating frequencies
so they can easily be contacted.  One effort,
called WOTA for "who is on the air" is tied into
logging programs.

But, of course, APRS already has a global system,
so all we have to do is to include our operating
frequency in our packets if we are actively monitoring
a voice freq.

In the past, Frequency  has not been particularly
highlighted, but it is very important and useful for
most mobiles because they usually have a live operator
present and usually he is monitoring his favorite
repeater.   We just need to be consistent in how
we report it.

This way, not only can you click on the APRS FINDU
web page to see where someone is while mobile
(live), you can also see what his voice operating
frequency is too.  In the future we hope to solidify
this construct so that it can easily be parsed in the
FIND data base too.

For example, see:   http://map.findu.com/we4apr-9

You will notice my beacon contains the text:

     "147.075MHz & VoiceAlert 14439"

The 147.075 is the local repeater I always monitor,
but the "VoiceAlert 14439" is always guaranteed
to work, since the APRS side of the radio is always
there and the volume is always up (though squelched
by CTCSS-100).  But he can always be contacted
if within simplex range.

I would like to encourage all APRS mobile operators
that  do consistently monitor a particular frrequency
to please include it in your packet and in the standard
format above so we can build a parsing system to take
full advantage of it.

The format is

FFF.FFFMHz....remainder of position comment text

Notice that this is exactly 10 spaces which is also
perfectly matches the 10 character wide window
on the front panel of the D7 and D700 radios,
making it a pleasent display of someone else's
operating frequency when it comes in.

Notice how my beacon is also carefully crafted
to show the Voice Alert info also.  Here is how it
flashes on the D700 panel on recepit:

WE4APR-9:
147.075MHz
-VoiceAlrt
 144.39

On the D7 display only the first two
lines are displayed:

WE4APR-9:
147.075MHz
-VoiceAlrt

Anyway, I would like to encourage everyone to
begin using this format.  If we can standardize
on it, then maybe we can get future radios,
and HAMhuds and other display devices to not
only display this info, but to automatically insert
it into our packets whenever we change the radio
knob.

Someone even wrote a little PIC device to hang
on the D700 serial port to query the radio's
frequency and then to write it into the radio's
transmitted beacons.  This way, the person's
operating freuqency was always known, even if
he QSY'ed.

For more info on this, please see:

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

de Wb4APR, Bob



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