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[aprssig] 2 HOPS (3 ways)

Keith VE7GDH ve7gdh at rac.ca
Wed Aug 29 19:11:05 UTC 2007


Joe NE3R wrote...

> Would WIDE1-1,WIDE2-1 be inappropriate for a fixed station?

WIDE1-1 would never be appropriate for a fixed station unless the ONLY
digi it could hit directly was a WIDE1-1 only digi... i.e. a "home fill in" 
digi that responds to WIDE1-1 and nothing else.

The recommended path in North America for fixed stations is WIDE2-2.
However, if you happened to live somewhere like Colorado, you might be in
the shadow of a digi that was at 10,000' + that had a huge footprint. In
that case a one hop path of WIDE2-1 might be appropriate.

In your case, there might not be any "WIDE1-1 only" digis within earshot of
you. The WIDEn-N digi near you should also respond to it, but if there were
a dozen or two WIDE1-1 digis scattered here and there around you, using
WIDE1-1 from a home station (with presumably a much better antenna than the
average mobile station) you could be firing off every one of those WIDE1-1
digis simultaneously. That would be considered QRM. The WIDE1-1 digis are
intended to help mobile stations that don't always reach a WIDEn-N digi
directly. This could be caused by multi-path, being blocked by trees,
buildings, hills, etc. or whatever. Fill-in digis are typically home
stations in areas with hilly terrain but that can be heard reliably by at
least one WIDEn-N digi (or perhaps an IGate).

I would recommend either a path of WIDE2-1 if the nearby digi covers all
of the areas you want to get to, or, if it doesn't, then use the generic
WIDE2-2, or even move from generic paths to a specific one. If the nearby
WIDEn-N digi was the ONLY WIDEn-N digi you could hit, there would be no
real advantage of specifying that digi instead of a generic path like
WIDEn-N. If on the other hand you could hit two or more WIDEn-N digis and 
you wanted to specifically "reach" a particular direction, you could specify 
a particular digi after the first one.

Again, looking at your own beacons that have made it to an IGate, there is
really only one digi that you can hit direct... apparently N3KTX-2. You have
been digipeated at least 1605 times through that digi between May 25 2007
and today - Aug 29 2007. The ONLY other digi you have gone through and made
it subsequently to an IGate was the home station KB3LVX which was acting as
a digi. You were gated after going through that station two times. Well,
it's possible it was more than that. The APRS server could have thrown out
dupes heard via that digi that were identical to beacons you transmitted in
the previous 30 seconds. Presumably your beacons are always identical if you
are a fixed station... presuming that you don't have a GPS connected. Given
that you were only effectively heard by KB3LVX two times, it would appear
that for all intents and purposes, the ONLY digi you can be heard by
directly is N3KTX-2.

The choice then becomes whether that digi has a large enough footprint to
reach the area you are in interested 25 miles to the NW or not. If it
doesn't, then your choices are to use a longer generic path, or to specify
one more specific digi that is off to the NW and that can be heard in the
area 25 miles to the NW that you are interested in.

What is 25 miles to your NW? Are there any digis in that direction? What is
the terrain like? Your questions are good ones, but understanding how
WIDEn-N (and WIDE1-1) digis work would help you understand the
logic behind what path to use. See...
http://web.ew.usna.edu/~bruninga/aprs/fix14439.html
Also www.nwaprs.info/fixedstationsettings.htm although this site
doesn't seem to emphasize that home stations should NOT use WIDE1-1.
Other than that, there lots of useful information on the site.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"






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