[aprssig] Automatic omni DF query

Robert Bruninga bruninga at usna.edu
Mon Feb 9 16:52:39 EST 2009


>> My new T2-301 trackers are frequency-
>> agile and can measure incoming signal 
>> strength, so it occurred to me that it'd be 
>> useful to define an APRS query that'd 
>> cause all capable stations to QSY 
>> their receive side to the specified 
>> frequency for a second, take a reading, 
>> and then come back and report what they 
>> heard in omni-DF format.

Yes, I have been trying to get that done for years.  I am hoping
it will all be part of the FREQUENCY QSY format.  We need the
FREQ QSY command format for several reasons:
1) To request someone to QSY to our freq
2) To auto-qsy a traveler to the local channel
3) To auto-qsy to a certain special net
4) To auto-QSY to a IRLP or Echolink node
5) To auto-QSY to take a DF reading

I had worked up a complete set of detail commands, levels of
action, and levels of denial, such as when to automatically do
the QSY, when to prompt the receipient to do it, or when to do
it anyway if not denied in X seconds, etc...  I'll have to dig
to find the docs.

But I do think it is important to think about all these
different QSY functions and make them part of a system from the
beginning so that we don't have to fix it later...

And the AUTO-DF is really something we have needed for years.
I'm so glad to hear you are considering it!

Bob, Wb4APR

> >     Before anyone asks, these particular units won't work 
> for 121.5 - I've
> >     only been able to get them to receive as low as 127 MHz.
> > 
> >     Based on some experimentation with a service monitor, 
> it looks like the
> >     usable RSSI range is roughly -128 dBm to -68 dBm.  If 
> I'm reading my
> >     conversion chart right, for a 50-ohm system that's a 
> little more than
> >     the standard S0-S9 range.  Seems kind of low at the top 
> end, but I'll
> >     have to do some field testing and see what I get.
> > 
> >     What I'm thinking of is something like this:
> > 
> >     ?DF146.520?<optional footprint>
> > 
> >     The response should be a DFSshgd omni-DF extension 
> followed by the
> >     frequency.  I'd prefer the frequency to be a standard 
> part of that
> >     response, so clients could be made smart enough to 
> separate out multiple
> >     DF plots.
> > 
> >     Comments or suggestions?
> > 
> >     Scott
> >     N1VG
> > 
> > 
> >     _______________________________________________
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> >     aprssig at tapr.org <mailto:aprssig at tapr.org>
> >     https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
> > 
> > 
> > 
> > 
> > -- 
> > Wes
> > ---
> > Where there's silence, there is no Hope.
> > 
> > 
> > 
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