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[aprssig] Ultimate APRS digi

Robert Bruninga bruninga at usna.edu
Fri Nov 19 00:35:57 UTC 2010

New title for discussion.  

I have added drawings at the top of APRS.ORG showing what I
consider the ultimate APRS digipeater for greatly minimizing
local congestion on 144.39 (or other country's freq):

1) Leave the 144.39 network just like it is now. (so it still
works for visitors)
2) Provide an alternate INPUT channel (144.99?) TNC and receiver
at every big digi.
3) The PTT/TXaudio of that alternate TNC is connected to the
existing 144.39 XMTR.
4) 9600 baud UHF packets are also cross connected to 144.39 at
1200 baud
5) The eXternal Carrier Detect (XCD) lines are diode-ORed to
both TNC's PTT lines.
6) 9600-to-9600 UHF packets can selectively remain on UHF only
for future apps

The result is vastly improved local user reliability since their
input packets on 144.99 do not have to compete with any of the
144.39 congestion.  Yet 144.39 still has ALL info for ALL users.

Until someone designs such a 3-input hardware, the closest I
know of would be a KPC-9612 and another TNC combined at the
site.  Its not the ultimate, but is the closest we can come for

If there are better ideas, lemme know.  But my fundamental
principle is that ALL normal local info resources should appear
at 1200 baud on 144.39 national channel.  But by splitting all
user inputs to alternate channels, the 144.39 can have 5 to 10
times the capacity is has now.


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