[aprssig] Impossible to be digi+something else? (DWAIT=0)

Frank Knobbe k4fhk at knobbe.us
Wed May 18 11:27:02 CDT 2016

On Wed, 2016-05-11 at 09:21 -0700, Bill Vodall via aprssig wrote:
> > I'm curious because I'm doing some research on an idea for improved
> > digipeating, and it requires using an external program with a KISS TNC. As
> > such, I'd like to be able to selectively decide whether my station is
> > "polite" or "impolite" on a per-packet basis (assuming impoliteness is still
> > preferred digipeater behavior).
> Perhaps related is the viscous digipeating currently supported by
> APRX.   While theoretically controversial, some users find it performs
> well.  The concept is for a low level digi to not repeat a packet if
> it hears somebody else digipeat it. Otherwise, after waiting a short
> period and not hearing a transmission - it digipeats the packet.

Yup, that's a great feature of aprsx. My Igate runs aprx and also acts
as a viscious fill-in digi. It only does this for directly heard packets
(non-digipeated, but regardless of path -- WIDE1 or WIDE2). Once a
packet has been heard directly, it will wait up to 8 seconds and see if
another (high) digi is digipeating it.

If the heard packet has not been digipeated (high digis didn't hear it),
mine will digipeat it. If someone else (like an area high-digi) has
digipeated it, mine will ignore it and not digi it again. It cuts down
on congestion by avoiding unnecessary duplicate digipeating, while still
"filling in" when high digis did not digipeat a stations packet.

I think staying quiet, except when a directly heard packet has not been
digipeated by someone else, is very polite. 


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