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[aprssig] More efficient use of channel capicity throughshorterpackets

Robert Bruninga bruninga at usna.edu
Fri Oct 13 16:14:40 UTC 2006


> How about a 555 timer circuit wire-OR'ed to the CD circuit of
the
> TNC?  It could hold off transmitting if the channel is busy OR
if
> it's not time to transmit yet according to the 555?
Cheap/simple.
> No programming involved.

Yes, this bundling approach has been documented on the APRS1.2
addendum page.  We don't actually want to delay real-time
packets that much, but it is great for OBJECTS, etc.  Here is
the link:

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

It is actually a command to the local DIGI to cache some things
itself, such as some event objects, so that each such object
gets full CSMA protection at the digi and avoids collisions both
on the uplink and downlink..

Bob, WbAPR





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