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ZL3AI > APRDIG 23.04.03 09:23l 256 Lines 10609 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Apr 20, 7/8
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: RE: a few basic questions....
From: "Daron J. Wilson" <daron@wilson.org>
Date: Sun, 20 Apr 2003 17:50:00 -0700
X-Message-Number: 33
>I beacon a fixed home position for several reasons:
>
> a. So that if it drops off the air while I'm not home, I know I
>have a
>problem with the shack.
Hmm, hadn't really thought of that reason, that's interesting.
> b. Gives others a place to drop me a message if I'm not on the air
>with my mobile station.
Seems like having a packet station at home would better serve as a
message handling center than doing that on APRS?
> c. And gives someone with a low power tracker or mobile a station
>to
>relay to one of the local WIDE digi's.
This is certainly a great benefit, however there is no reason to beacon
in order for a mobile tracker to take advantage of that is there?
> It also gives me a station to demo my mobile unit to someone with
>messages, direction/bearing, etc. without filling someone else's inbox.
Again, could you still do that even though you weren't beaconing from
the home position?
Just trying to understand, thanks
73's N7HQR
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Subject: Re: a few basic questions....
From: Randy Allen <ka0azs@earthlink.net>
Date: Sun, 20 Apr 2003 21:08:03 -0400
X-Message-Number: 34
"Daron J. Wilson" wrote:
>> b. Gives others a place to drop me a message if I'm not on the
>>air with my mobile station.
>
>Seems like having a packet station at home would better serve as a
>message handling center than doing that on APRS?
We're only talking a quick 1 liner like "give me a call". Quite
frankly, I'm not interested in "traditional" packet and, given the
activity levels around here, would never have invested a radio, antenna
and TNC without APRS to play with. And I certainly am not interested
enough to set up a second station on another frequency for an occasional
message. And I am not going to set up a "traditional" connected packet
station on 144.39.
The station is going to be up anyway so that I can do a quick check
for local activity, weather, etc. and I don't feel that one beacon every
1/2 hour or so (not counting any relays from other stations) is
excessive loading. Of course YMMV depending on local conditions.
>
>> c. And gives someone with a low power tracker or mobile a station
>>to
>>relay to one of the local WIDE digi's.
>
>This is certainly a great benefit, however there is no reason to beacon
>in order for a mobile tracker to take advantage of that is there?
No, but same reasoning as above, the station is up anyway.
>> It also gives me a station to demo my mobile unit to someone with
>>messages, direction/bearing, etc. without filling someone else's
>inbox.
>
>Again, could you still do that even though you weren't beaconing from
>the home position?
Not really, the D700 needs a position beacon of the other station in
order to calculate bearing and distance. So if there is no beacon,
there's nothing for it to compare present position against. Messaging,
of course would not require a position beacon at the receiving end. But
if I don't get an ACK from home, and can still see a position, at least
I've narrowed the possible problems down.
>Just trying to understand, thanks
No problem. I realize my reasons aren't going to be everyone else's
reasons, but as long as I don't violate Part 97 or the spirit of good
Amateur Practice, I don't see any problem with doing it the way that
makes sense for me. And of course, if it were to become a problem, a
few key strokes in configuration or hitting the power button solves any
issues quickly.
73
--
Randy Allen, KAĜAZS
EC, Montgomery CO Ohio
OH Dist. 3 ARES Web Page:
http://www.qsl.net/ohd3ares/
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Subject: RE: a few basic questions....
From: "Ev Tupis (W2EV)" <w2ev@arrl.net>
Date: Sun, 20 Apr 2003 21:36:27 -0400
X-Message-Number: 35
"Daron J. Wilson" wrote:
>
>>>1. Automatic Position Reporting System as I understand it,
>>> so why do so many home stations (who obviously are in the
>>> same place all the time) beacon endlessly with their
>>> position? What is the benefit of this?
This is especially helpful to those home stations that have the potential
of becoming mobile with little or no notice, such as those in tornado-belt
trailer parks or near the San Andreas fault.
Having home/fixed stations beaconing endlessly provides an easy mark for
radiolocation should "the big one" hit and you needed to find your home
after the aftershocks die down.
>>2. The weather data is very interesting, and I have a home weather
>> station putting data on the internet already. But then I got to
>> thinking, if we are concerned with channel crowding, what roll in
>> Automatic Position Reporting do fixed weather stations provide?
>> Perhaps it would be better if they output their data on the packet
>> network or a dedicated weather network and then it were picked up
>> since their position doesn't change?
Ahhhh, but if they did this, no one would see that it is *me* who has put
forward all of that effort to create a WX station in the first place. It's
cool for me to do that AND see an icon on everyone's map with my callsign
on it. It's sort of a high-tech version of urban-tagging. My symbol shows
up on your computer because I put it there. It's not about the
weather...it's about ME putting the weather report there.
With a giggle and
Tongue-in-cheek,
Ev, W2EV
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Subject: Re: a few basic questions....
From: Miller Scott Contr 30SCS/FTI <Scott.Miller@vandenberg.af.mil>
Date: Mon, 21 Apr 2003 02:19:21 -0000
X-Message-Number: 36
I run aprsd under Debian Linux and it's been rock solid. At least, since I
made a minor source code tweak so it'd work on my AlphaStation. It's the
only IGATE software I know of that's designed to run as a network service
with no user front end. I guess it's really a matter of the KISS principle
- I'm not running any more than I have to on the box. Though since I've
been using my KPC3 for tracker testing, I've been running soundmodem, which
keeps my processor at 4% all the time.
I wouldn't recommend running on a non-x86 architecture for the faint of
heart - as far as I know I'm the only person running aprsd on an Alpha, and
it just plain didn't work at first - but a good minimalist Linux install
with no GUI baggage is pretty much bulletproof when done properly.
Scott
N1VG
(FWIW, I'm not a Linux zealot - OpenBSD is my favorite *nix OS, but it just
doesn't have the ham radio support of Debian.)
-----Original Message-----
From: Randy Allen
To: TAPR APRS Special Interest Group
Cc: TAPR APRS Special Interest Group
Sent: 4/20/03 5:05 PM
Subject: [aprssig] Re: a few basic questions....
I will probably eventually set up an I-Gate as well, but can't bring
myself to lose the stability and reliability of my dedicated DOS machine
to move to something that will talk with my LAN and cable modem.
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Subject: Re: a few basic questions....
From: "Spider" <spider@rivcom.net>
Date: Sun, 20 Apr 2003 19:19:59 -0700
X-Message-Number: 37
----- Original Message -----
From: "Daron J. Wilson" <daron@wilson.org>
To: "'Spider'" <spider@rivcom.net>
Cc: <aprssig@lists.tapr.org>
Sent: Sunday, April 20, 2003 5:40 PM
Subject: RE: [aprssig] a few basic questions....
>>>1. Automatic Position Reporting System as I understand it, so why do so
>>>many home stations (who obviously are in the same place all the time)
>>>beacon endlessly with their position? What is the benefit of this?
>>
>>It allows others to know that they are there?
>>The arguement about if a stations moves or not is moot.
>
>I disagree. The whole point to having a dynamic positioning system is
>that the data transmitted indicates change. If this were not the case,
>we could employ a static system that would simply pull data from a
>license database, draw a quick map, and be done (perhaps like a grid
>square map).
You seem to have all the answers you asked for! It's still a moot point.
The transmission indicates the station is on line and still there. Client
software has expiration times. For me, I do not want to see a bunch of
dead stations....I choose to have stations expire every 80 minutes. If
they do not beacon they are gone within that time frame. You can not depend
on a single transmission to indicate the station exists. If you missed
receiving a tranmission or if the station failed, or was just turned off,
you'd never know it. There is nothing in the world that says that data
transmitted indicates change....but I suppose the time changed, so you
might be right. And, simply, APRS has evolved into more than just position
reporting....more than what was probably imagined during the original
concept.
Let me say I am not against weather data,
>I will likely add a weather station connection at some point as well.
>My point was that there is in fact congestion on a network designed and
>implemented for position reporting, and one way to reduce that
>congestion is to not propagate signals that are not of dynamic
>positioning data. More is not necessarily better for data. A very
>basic understanding of data should show that in order for the data to
>provide valid information it must in fact be accurate (or reasonably
>so). A quick bit of math would show that every bit of inaccurate data
>decreases the reliability of the total data collected.
Yeah and accuracy is in the eyes of the beholder. Repeatability is more
important. And I am certainly not a bean counter.
If I can repeatably shoot and hit my target at 800 yards, with my accuracy
being off being off 5 or 6 inches or maybe
more at a time in all sorts of directions, the accuracy would mean
nothing...I still hit my target no matter how much math
you do.
You can have 10 weather stations in a star pattern. 9 of them will read 74
degrees. 1 of them reads 76 degrees. Which ones are
more accurate? Obviously, not enough information to make a determination!
More data is needed. However, in all probability your
math with tell you the 9 are more accurate, which may not be the case at
all. Why, because someone set a standard to go by
and the standard says (by the math) the chances are good the nine stations
are correct.....in the eyes of the beholder.
Jim
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