--- In [email protected], James Ewen <ve6...@...> wrote: > > On Fri, Aug 14, 2009 at 11:53 AM, Broncus<fmhillho...@...> wrote: > > >> If you use a path such as WIDE1-1,WIDE2-1,MYCAR and have your vehicle > >> set to preemptive digipeat on MYCAR, it will be handled by the car, > >> but will look like this after. WIDE1-1,WIDE2-1,MYCAR* where the > >> asterisk (*) represents the has been digipeated bit. Any subsequent > >> digipeater fill-in or mountaintop will only look for a path that is > >> after the has been digipeated bit. > > > > I don't quite get this. But I think you are saying, the car would see > > the MYCAR (fromthe HT) and forward the beacon with the > > WIDE1-1,WIDE2-1 intact which a fill-in or WIDE digi would see > > and treat it like it came direct. > > No, exactly the opposite. The outgoing path in a packet HAS to be used > in the order it is listed. Using WIDE1-1,WIDE2-1 means that WIDE1-1 > has to be used before WIDE2-1. WIDE1-1 is supported in home fill-in > digipeaters, as well as the main WIDE area digipeaters, so any > digipeater will respond to that path. Once WIDE1-1 is used (and marked > with the has-been-digipeated bit which sometimes is shown as the call > of the digipeater followed by an asterisk "*"), then only a WIDE area > digipeater will act upon the WIDE2-1. > > If you use a named path such as PNDRVL,WIDE2-1, and you are not heard > by PNRDVL first, you will not get digipeated by anyone else. > > With preemptive digipeating, (which is only supported by Scott's OT2 > as far as I know), it will scan all of the aliases in the outgoing > path, and if it finds an alias which it is configured to act upon in a > preemptive manner, it will use that alias up. So if the path is as > above, WIDE1-1,WIDE2-1,MYCAR, and you have the OT2 set to act > preemptively upon MYCAR, then the OT2 would be able to digipeat the > packet even if the packet was heard directly, and neither the WIDE1-1, > nor the WIDE2-1 had been used up already. > > If the MYCAR alias is acted upon, the packet would end up looking like > it had been completely used up even though it hadn't been acted upon > by a fill-in nor a WIDE area digipeater. > > It's a little bit of a strange concept. It was based on the idea of > having a fully mobile self deployed network in support of a Search And > Rescue event. Each SAR team would carry an OT2 set up as a preemptive > digipeater set to act upon the SARn-N alias. > > Each SAR package would use an outgoing path of WIDE1-1,WIDE2-1,SAR7-7. > This would allow those heard by the regular APRS-RF network to be > digipeated normally. If however the SAR teams ended up in an area with > no APRS infrastructure in place, the teams would become their own self > deploying, self digipeating network, which would hopefully be able to > get tracking information back to the search HQ. > > Even in an area of digipeater coverage, the SAR network would digipeat > itself. There would be no flooding effect to the local network as the > SAR alias is not regularly supported by the main digipeaters. > > Make any sense? > > James > VE6SRV >
Thanks for the explanation. I think understand it but I will have to read this again after the trip and try it out to know for sure. Time for some vacation! Best regards, Fred
