[aprssig] PATH clarification when travelling
aprs at pe1rdw.demon.nl
Fri Jul 29 13:11:36 CDT 2005
Stephen H. Smith schreef:
> smithb at bpsmicro.com wrote:
>> [Apologies if this gets posted twice...]
>> Okay, I *think* I'm pretty clear on the new paradigm, but there's one
>> lingering question to toss out. It involves a mobile taking a trip
>> that'll involve travelling through areas that have upgraded to the
>> new paradigm, and some that haven't.
>> If one were to set the path to, say "RELAY,WIDE1-1,WIDE2-1", would
>> that be the best compromise? I'm well aware that stopping to change
>> the path as you entered each area would be ideal, but without
>> adequate info (eg. a centralized database) of what PATH works best in
>> what areas, that's a tad difficult (not to mention inconvenient in
>> some cases).
>> Specifically, if I'm in an area where RELAY has been discontinued,
>> and a local digi hears the above packet, will it just ignore the
>> RELAY and deal with the WIDE1-1? Or will the fact RELAY is in the
>> packet cause the whole thing to be tossed out?
> Packet paths are processed SEQUENTIALLY, not in parallel. The first
> hop in the string MUST BE USED FIRST before any subsequent hops are
> acted on. If RELAY doesn't get processed first, and marked as
> "used" in the example above, you are not going to go anywhere! A
> full discussion of this issue is on my website at:
> In the case of the D700, or a TinyTrack, alternate paths can be stored
> in the device (5 in the case of the Kenwoods, 2 in the case of the
> TinyTrack) and then selected as needed enroute. You might store a
> path of "RELAY, WIDE, WIDE2-2" in one mode, and "WIDE2-2" or
> "WIDE1-1, WIDE2-2" in the other.
I think the only widely used digipeater option that can do preemtive
digipeating is digi_ned, the in the usa widely used kpc digipeaters
can´t do it and I doubt they ever will because the room in the rom is
This problem will most likely be around for a few years yet.
73 de Andre PE1RDW
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