[aprssig] conflicting APRS intructions
gary at garyndenise.org
Fri Oct 23 18:06:01 EDT 2009
As a fairly new ham and APRS user (and now digi/igate operator), I've
noticed that a stated goal for APRS is somewhat conflicting.
Take, for example, the statements (from aprs.org): "APRS is not about
vehicle tracking. It is a single information resource channel ", "APRS
is not about dumb-one-way-trackers. ", and "And finally, that all
mobiles would have simple displays to keep them in communicaitons and
aware of their surroundings."
This implies 2-way communication. Yet, elsewhere on APRS.org the
solution for "dead zones" in the APRS network is a "wide1-1" digi -
WIDE1-1 fill-in digis provide a way for mobiles in a dead zone to be
able to be digipeated out without that same digipeater adding to the
congestion elsewhere by also digipeating every other packet heard from
everywhere else. In otherwords, it only responds to 1st hop packets
from mobiles and/or stations that explicitly use the WIDE1-1 hop first
in their path.
This is in direct conflict with a stated goal of 2-way communication,
as the "fill-in" is only repeating packets FROM the mobile station,
and wouldn't repeat TO that mobile station any packet (unless it
happened to have an unused WIDE1-1 hop specified in its path - which
If the mobile can't talk to the major WIDE2 digi's in the area, they
likely can't "hear" them either. The WIDE1 "fill in" digi, in this
case, only serves to support "dump-one-way-trackers" and does nothing
to facilitate 2-way communication between the station in the dead zone
and the rest of the APRS network.
There are other areas that I found conflicting as
To this end, I really like what aprx is doing with the experiment of
"viscous digitpeating." This seems to be a BETTER solution to black
holes than the above mentioned "fill in" digi's (which are nothing
more than "dumb-tracker" relays.) It doesn't completely solve the
problem, as the aprx digi can't know if a local mobile can hear other
digi's, but I think its a step in the right direction.
Gary / K3WOW
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