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[aprssig] 9600 APRS

Patrick Green pagreen at gmail.com
Fri Apr 3 08:36:12 UTC 2009


I've used APRSD to Igate a region onto UHF 9600.  For example before I
went to Germany, I redirected all of the German callsign data to
430.55 with a rubber duck on the back of an old Kantronics D4-10 (so
the traffic was for my use).  You'd be surprised how much data you can
get in there before it gets too busy.

73 de Pat --- KA9SCF.

2009/4/1 Wayne Sanderson <whsander at gmail.com>:
> My increasing involvement in Emergency Management in NJ has gotten me back
> into APRS with a vengeance, and my Kenwood rigs are running hot. Running
> slow 1200 baud with random packet intervals and packet collisions seems kind
> of static. The newer rigs will run 9600 APRS, but there is no 9600 network
> for them.
>
> We have better features built into the Kenwood radios than we actually get
> to use because the network at 144.39 is still 1200, hence very little 9600
> ops- mostly satellite spotting. Since we allow these features to languish
> unused or at least under used, no other radio manufacturers seem to feel the
> need to incorporate them in their product lines. Now we have lost the
> TH-D7s. ( I don't really believe that decision was made because of toxic
> chemicals in the PCBs... Do you?)
>
> How about something a bit different? Suppose, as an experiment, here in
> Central NJ where there is a pretty dense signal cluster, we were to set up a
> 440 UHF 9600 APRS digi at as high a point as we can get, running as much
> power as we can manage.
>
> Instead of having a conventional digi, have a computer hooked to 2
> radios/TNCs, one running at 1200 on 144.39, the other at 9600 on 440 UHF.
> Have the computer APRS application record all the received packets over a
> three minute period of monitoring 144.39 1200 operations, compile them into
> one long data stream and at the end of that 3rd minute transmit that three
> minute take from 144.39 1200 onto the 440 UHF band 9600 channel in one long
> burst. In the intervening minutes between that digi-burst and the next, 9600
> UHF APRS units can transmit position packets, which will not be digipeated
> immediately but will be scooped up by the computer and incorporated into the
> next data burst, and can be cross banded to 144.39 at 1200 as well.
>
> If I am correct, this will cut packet collisions way down, and on the UHF
> 9600 channel the air will be clear, allowing for greater distance RX and TX
> in between digi-bursts, at least until a large number of people start
> running APRS at 9600 on UHF and we eventually get QRM. And even if a large
> number of people eventually do run 9600 on UHF, the capacity of the channel
> is as much as eight times that of 144.39 because of the speed increase. That
> gives us room for more content, larger packets, longer messages, in short-
> More room to play with.
>
> I am not a programmer, and so I can't make this happen by myself. All I have
> is some money for equipment and the desire to see this happen. One of the
> talented APRS programmers out there would have to get interested in this.
> Any takers?
>
>
>
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