To the Preacher. (Was RE: Emergency comms. Was RE: [aprssig] Igates Are A Fair WeatherSolution (was:
bruninga at usna.edu
Wed Aug 31 10:15:54 CDT 2005
You seem to missinterpreting my use of the word
"local" as being a geographic term. It is not. It
is an RF term, and in APRS, it means all those
stations that are close enough to you so that
you can all share 1200 baud RELIABLY without
lost packets. In some areas, that might be
15 miles. In others, it might be 150 miles.
Has nothing to do with geography. It has to do
with frequency saturation. That is why all APRS
software should display the ALOHA circle to users
so they can see what their "local" network
really is... Bob, WB4APR
>>> dave at emv.co.uk 08/31/05 5:27 AM >>>
All understood. But.....
The main difference here (UK) if I've failed to get it across before, is
that WE DO NOT have an abundance of IGATES. (Sorry to shout from the
Hence, for many of us in the UK, a "Wide" area of coverage is what we
desire. Local communications (small area) is fine, and well served in
parts of the UK, but not others.
We also do not have the same percentage of licensed (and active!) ham's
in the population, that makes a wide area coverage even more useful than
Also, I and others have a desire to track and message friends etc, who
travel all over the UK, and sometimes Europe. Currently, APRS just
about does it, but as you point out, not reliably.
Using your "Local" area plan, this would not be possible. (And as I'm
slowly finding, using the ISS is problematical too)
Again, we DO NOT have a large selection of IGATES to use (licensing
restrictions) and getting to them for what we wish, needs as you call
them "Abusive" paths. (Sorry to shout again.)
>From what others have said recently in any case, it would appear that
many US users are figuring out how to "abuse" the system in any case, to
get a similar result to what I and many over hear wish to use it for.
Weather stations in the southern US obviously have a valuable
contribution to give the community as a whole. In the UK, as far as I
can see, they just add to the QRM, also the "Traffic" counters. We know
the roads are congested, so why broadcast the fact, locally or
Yes, short paths, and small "Aloha" circles make for reliable comm's,
but that is best provided for in a real emergency by dedicated digi's on
a separate frequency, away from the crowd for that very reason. Also,
you are not then relying on any existing infrastructure you have no
control over, should the lights suddenly go out.
OK, me bum's back on the pew.....
Dave B. 'WBX
> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert Bruninga
> Sent: Tuesday, August 30, 2005 5:59 PM
> To: aprssig at lists.tapr.org
> Subject: Emergency comms. Was RE: [aprssig] Igates Are A Fair
> WeatherSolution (was: "Finito")
> This is not directed at the authors of these words at all,
> but out of context, they offer an opportunity for a sermon...
> >> but if those 150 to 250 stations[you see routinely] are
> >> very often, your network is dropping a _lot_ of packets.
> >So what if a lot of packets are being dropped? ...
> >there are multiple transmissions of the same data
> Ah, a good example of the number #1 perception by some users
> of APRS which is killilng its reliability and its original
> communications intent.
> The above "THE MORE THE BETTER" approach comes from the basis
> of a person's perception of the goal of APRS is to fill up
> the map with as many stations
> as possible, 24/7. THe more the better. Latency,
> delays or low probability of success don't matter compared to
> the fullness of the map.
> When in fact, exactly the OPPOSITE is the goal of APRS as a
> tactical-real-time reliable communications system for local
> use. In this case, it is RELIABILITY and MINIMUM LATENCY for
> local users that counts.
> (Which means the FEWER the better)...
> Everyone should notice that these two are perfectly mutually
> exclusive. Too many video voyers have tilted the predominant
> public perception of APRS as the former. A mere video or
> internet game with no local practical purpose due to lack of
> reliability and/or too few local users.
> Whereas the volunteer public service oriented, local users
> who want to use APRS reliably to acctually accomplish a given
> communicatinos mission are lost in the QRM generated by the former.
> Continuing the thought of more and farther is better:
> > Even in the face of extreme QRM, if a signal is strong
> enough... it
> > will be registered and heard.
> > As to emergency comm's. You cant beat CW...
> > ever tried to enter ... into the keypad of a TH-D7 under duress ?
> Well, my experience is that for events, we have 10 times more
> volunteers that can stumble out a message on a TT-pad (APRS)
> than show up that can send CW on their HT.
> Don't be a video voyer. Get out there and DO SOMETHING with
> APRS. Shrink your map and expectations, and then use the
> clear channel that results to use APRS to reliably facilitate
> portions of all of your local club activities.
> Again, this is not at all directed to the original authors of
> those out-of-context words, beacuse the original point was
> elsewhere, but it gave me the opportunity to turn and preach
> to the choir...
> de Wb4APR, Bob
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