[aprssig] I almost understand WIDEn-N

[Joseph M. Durnal]

Yeah, it is lonely, but more lonely when your TNC doesn't seem to work
(detects data carrier, but nothing displays in the terminal), but that
is another story.

I think I get it, basically the little n doesn't really do anything.
It looks like WIDE2-2 is the way to go for a fixed station, would that
be fine for mobile too?  In the mid west, especiallly to the north,
there dont' seem to be do many digis.  My summer 2009 vacation plans
have me driving out I80 or I90, I thought APRS might be a neat add on
to that trip.

I'd also like see how we can use APRS for local emergency
communications and short message traffic, somehow, I've found myself
as an ARES AEC in my county.

And last but not least, APRS tracking would be a great service to the
Moutnain Club of Marydland during their biannual hike accross MD on
the appalation trail.  This year we found ourselves often wondering
where the last people (MCM organizers who were supposed to be just
behind the last participent) on the trail were when between
checkpoints.  Sending a ham with those folks with APRS would not only
be whiz bang neat, but pretty useful for that event.

(I got way off of my own topic here)

73
Joe
NE3R


On 5/26/07, Keith VE7GDH <ve7gdh at rac.ca> wrote:
> Joseph NE3R
>
> > WIDEn-N, I understand what the second N is for, I think. Basically
> > after each digi the value of N goes down by one. What is the purpose
> > of the first n?
> >
> > I'm curious what the difference would be between WIDE2-2 or WIDE3-2.
>
> Just some additional comments to Herb's reply... I see you have already got
> NE3R on the air, but it must be rather lonely in the middle of the Pacific -
> hi! http://map.findu.com/NE3R. If you had multiple stations running under
> your callsign, each would be made unique by a different SSID. (Ummm...
> secondary station identifier??) When you use NE3R the implied SSID is -0,
> but "dash zero" isn't used. You could have up to 15 other stations running
> as NE3R-1, NE3R-2 etc. That SSID doesn't change. When specifying a digi path
> e.g. WIDE2-2 the "WIDE2" is an alias. The "-2" is an SSID, but with a
> special function. When your beacon goes through a digipeater, it decrements
> the SSID to indicate how many "hops" are left. When it gets to zero,
> it isn't digipeated any more. A path of WIDE7-7 (not recommended!)
> would indicate that you wanted go be digipeated seven times and that none of
> the hops had (so far) been used up. However, in the real world (at least in
> North America) seven hops would be unrealistic and anything more than two
> (or three) hops would be considered QRM. APRS is after all for "local" use
> and trying to propagate a beacon via 7 WIDEn-N digis would be very bad
> practice unless you had some kind of an emergeny going on. Someone could use
> a really stupid path of WIDE2-7 and (if not stopped by up-to-date digis that
> try and trap such paths) could potentially go on and get 7 hops even though
> it starts out by saying that the user really wanted two hops. Stupid paths
> would of course be more than frowned upon! I'm just trying to give a further
> example of what the n-N means. The first number is actually part of the
> alias and indicates the desired number of hops via digipeaters. The second
> one (really an SSID) indicates how many hops are left and does get
> decremented by one each time it goes through a digipeater.
>
> In your example of WIDE2-2, you would be requesting two hops and one are
> used up yet. In WIDE3-2 you were presumably requesting three hops by
> starting out as WIDE3-3 and the first hop had already been used up by going
> via a digipeater and it spat it out the other side as WIDE3-2 and the next
> digi it went through would decrement it to WIDE3-1 and after one more digi,
> it would be down to zero (WIDE3-0) and any other WIDEn-N digis that heard it
> wouldn't take any action.
>
> Again, the recommended path in North America is WIDE1-1,WIDE2-1 for mobiles.
> Any "home fill-in" digi that responds to WIDE1-1 will act on it. If heard
> direct by a WIDEn-N digi, it will also act on it. Paths are used
> sequentially, so after the WIDE1-1 has been used up, it would get one
> additional hop from any WIDEn-N digi that heard the request for WIDE2-1. The
> reason home stations shouldn't use WIDE1-1 is that presumably they have
> better antennas and a good path to an adjacent WIDEn-N digi and don't need
> any additional help from a fill-in digi. A few (very few) places will need
> more than two hops to make it to a specific place... e.g. to an IGate. It's
> up to the individual to use a sensible path.
>
> If WinAPRS doesn't fill your needs, don't forget that UI-View is available
> at www.ui-view.org.
>
> 73 es cul - Keith VE7GDH
> --
> "I may be lost, but I know exactly where I am!"
>
>
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