Eastern Ontario APRS Tips
no longer maintained by Brad -
VE3BSM (@gmail.com)
Updates:
-
04 Sept '06 - Digipeater settings
recommendations tweaked to recommend WIDE1-1 only. There are now *too many*
Wide-area digipeaters in the area, causing some congestion of the channel.
-
25 Dec '05 - In the past month or
so, a new WIDE1-1 digi, VA3RLR, has been set up by the Rideau Lakes club at
Smiths Falls. This covers a nice hole in the south-west area. In addition,
VE3PGC (Cornwall) and VE3IWJ (Brockville) were converted to UIDIGI-based
software, which makes them even more compliant with the new paradigm. And,
VE3UEL (Kingston) and VE3MHZ (Belleville) are in the process of being
reconfigured to follow the new paradigm, and are nearly complete.
-
17 November '05 - VA3AAR digipeater
in Ottawa decommissioned. Replaced with VE3WCC-1 running new Paradigm.
RELAY,WIDE,TRACE will no longer be digipeated in Ottawa area.
-
8 Sept '05 - VE3DVQ digipeater in
Lavant upgraded to new paradigm.
-
17 June '05 - elimination of RELAY
in suggested paths (no longer required/supported in most areas)
-
17 June '05 - Southern Ontario now
almost 100% on new paradigm. "RELAY" and "WIDE" ignored, along with abusive
WIDEN-n paths.
-
05 May '05 - new PATH
recommendations
Executive Summary:
Mobile Stations: set PATH to "WIDE1-1,WIDE2-1"
Home Stations: set PATH to "WIDE2-1"
Digipeaters: set PATH to "WIDE2-1" and UIDIGI to
support "WIDE1-1" only
Beginner APRS:
Stephen Smith (WA8LMF) has written an excellent
"essay" explaining the concepts of digipeating and PATH selection. If you're new
to APRS (or even if you've been around the block (so to speak) a few times, you
may find it an interesting read. See:
APRS Digipeating and Path
Selection 101.
Details:
The APRS RF network is becoming very congested, especially
in the larger US cities. But due to a variety of problematic settings amongst
various APRS users; most commonly due to a lack of clear understanding of the
network; there are many cases of beacons being "broadcast" tremendous distances.
I don't know about you, but some of the "documentation" concerning APRS settings
has been a tad confusing, contradictory, or outdated.
As a service to local (Eastern Ontario) APRS users, I have
set up this page to be a collection of tips that will allow you to hopefully set
up your APRS rig to follow the most recent paradigm. The intent is to allow you
to get your beacons out to the nearest IGate and/or other local users on RF.
Please take a moment to look over Bob Bruninga's recent
page "Fixing the 144.39 APRS Network" at
http://aprs.org/fix14439.html. It's quite detailed, so
I will attempt to "water down" the recommendations to those most likely to apply
to our area, and also toss in some pointers not specifically covered on this
page. Eastern Ontario, and especially up towards Ottawa, is in the "medium-low"
range of user density. While we don't have a major density problem, there are a
few areas in town where a single beacon gets digipeated seven or eight times (if
you're running a Kenwood rig, you'll know when that happens).
The current wisdom is to eliminate the duplication caused
by RELAY digipeating, "WIDE"-only duplication, and excessively high "WIDEn-N"
values. In most parts of North America, every digipeater is within two hops of
an IGate, and digipeating beyond that is just noise. As "home" digipeaters get
updated, "RELAY" should be replaced by "WIDE1-1", and "WIDE2-1" lets a wide-area
digipeater handle your packet, but with only the one extra hop. Assuming
digipeaters properly implement "WIDEn-N" processing and callsign substitution
(unfortunately, not all in our area do), this can greatly reduce unnecessary RF
traffic.
Home Settings:
- If you can get to VE3WCC-1, VE3UEL, VE3STP or VE3PGC directly,
set your PATH to WIDE2-1. All of these "core" digipeaters are well
within range of at least one IGate, and between them cover most, if not all of
Eastern Ontario.
- If you can get to any digipeater that can get to one
of the above (which is pretty much *any* digipeater), set your PATH to WIDE2-2.
- Never include "WIDE1-1" in the PATH for a home
station unless you're running such low power that you can't get to *any*
WIDE digi, but you can get to a nearby 1-hop station. In that case, use "WIDE1-1,WIDE2-1".
- Never use any n-n number higher than 2-2. All this
does is add to the traffic without any benefit.
- Recognize that "WIDE2-2" is *not* the same as "WIDE,WIDE".
The latter is to be strongly discouraged, since it tremendously increases
packet duplication. In addition, use of "TRACE" is to be discouraged as
well, since it is the same as an extra "WIDE" and doesn't add any value.
- Set your beacon rate to no higher than once every 20
minutes, and preferably once every 30 minutes.
- UI-View users, note that your PATH must be preceded
by "APRS", as in "APRS,WIDE2-1". It's unclear if other software packages
require this.
Digipeater Settings (in addition to above):
- We do *not* need any more Wide-area digipeaters in
the area. If you wish to set up a digipeater, consider making it a
Local-area (aka WIDE1-1) digi only. This will assist your local
mobile/portable/low-power users in getting into the network, without causing
excessive congestion as beacons are duplicated multiple times. If you are
unsure, contact Brad (VE3BSM) by clicking the contact link at the bottom of
the page for advice on how best to serve the APRS community. Brad can
probably point you to specific information for the TNC/software you intend
to use to clarify the proper setup procedure.
- Review the instructions at
http://aprs.org/fix14439.html, which
pretty much works fine for our area as well.
- If mobile operators in your area can be reasonably
expected to reach a WIDE digi, there's no need for any extra "RELAY" digis.
- If mobile operators in your area can be reasonably
expected to reach one of the "core" digipeaters listed above directly (or,
more accurately, any digi within 1 hop of an IGate), there's no need for any
extra WIDE digis. More digis is *not* a good thing, generally
speaking.
- If setting up a special-purpose digi (ie. to allow
portable use relevant to an event of some kind), set your UIDIGI alias to
your callsign only, and set the portables to include your callsign in their
PATH (eg. "VE3BSM,WIDE2-1" is what my portable is set to, with my mobile
set up as a digi with only "VE3BSM" in the UIDIGI).
- If your digipeater supports duplicate checking, make
sure it's enabled and set to a sufficiently high value (15 seconds is the
recommended minimum, 28 seconds the preferred value).
- Ensure that you have your station icon set up with
the correct overlay to indicate what type of digipeater you have set up. See
http://aprs.org/newN/n-n-overlays.txt for information
on how to do this.
- It is polite to have your digi beacon include contact
info for the trustee/owner of the digipeater. That could be the owner's
callsign (if different from that of the digi, e-mail address and/or web site
URL). People *should* be able to contact a digi owner without a lot of
research.
Mobile Settings:
- The preferred PATH for mobile users is "WIDE1-1,WIDE2-1".
Area digipeaters are nearly finished migrating to the new paradigm, and RELAY,
WIDE and TRACE are no
longer supported.
- If you travel to the US or Southern Ontario, you'll
most likely need to
remove "RELAY". In some highly congested areas, digi owners are actively
ignoring beacons that don't follow the new paradigm, and you'll find your
packets going nowhere.
- You should never need to set an n-n value higher than
2-2 or maybe 3-3 for mobile use in Eastern Ontario (and also most of the US). We have very good digipeater coverage, and almost all of them can get to one of the "core" digipeaters mentioned above within one or two hops. This will get you
to an IGate, and wide RF coverage.
- Again, recognize that "WIDE2-2" is *not* the same as
"WIDE,WIDE". The latter is to be strongly discouraged, since it tremendously
increases packet duplication. In addition, use of "TRACE" is to be
discouraged as well, since it is the same as an extra "WIDE" and doesn't add
any value.
- Set your beacon rate to no more often than once every
2 minutes. If you're lucky enough to have a TNC that supports smart
beaconing (which doesn't apply to us Kenwood users), set the "timed" beacon
rate to 20 to 30 minutes, and the traveling rate to roughly once every 2km
(higher if you spend a lot of time on the highways, and way higher if you're
aeronautical-mobile).
Comments welcome. Feel free to e-mail me at "my callsign @ gmail.com".
VE3BSM