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ZL3AI > APRDIG 24.11.06 02:44l 164 Lines 6057 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 29 #20, 1/1
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To : APRDIG@WW
Today's Topics:
1. RE: APRS DF reporting (scott_at_opentrac.org)
2. RE: APRS DF reporting (Robert Bruninga)
3. WinAPRS to work with an MFJ 1278 tnc (Chris Bouck)
4. Re: WinAPRS to work with an MFJ 1278 tnc (VE7GDH)
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Message: 1
Date: Wed, 22 Nov 2006 10:50:11 -0800
From: <scott_at_opentrac.org>
Subject: RE: [aprssig] APRS DF reporting
>I disagree, it is a very improtant issue. Bearing lines have
>an estimated length relative to the knowledge of the person
>doing the bearing line. That information must be included in
Speaking as someone who once spent a night chasing a marine EPIRB across an
inland mountain range, I disagree. The COSPAS/SARSAT hit gave a false
impression of where the search area should be, and all of our a priori
assumptions were wrong. I think I'd prefer to start with a generous
estimate of the maximum possible range and use that. If the lines all
disappear before reaching convergence, you're searching in the wrong place.
Ultimately, it should be up to the client software to limit the length of
DF lines. Especially in the case of a SAR operation, you're likely to have
more drivers than skilled DF operators. Even if you only have one, they
should be at the mapping console interpreting what they're seeing and
directing the searchers. Having them ride along with an autonomous DF
system that has no user interface other than an on/off switch would be a
waste.
For manual DF bearings, there's obviously a little more operator skill
involved. Still, I don't think it's ever safe to guess at the range. I've
been on t-hunts where the transmitter was a tiny unit buried underground
with a 19" wire antenna shoved into a dry weed (ok, that was me), and
others where the transmitter was a 60-watt mobile with a 4-element quad
pointed straight at the starting point.
And around here, every once in awhile your kerchunker might turn out to be
someone talking on a repeater in Hawaii...
Scott
N1VG
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Message: 2
Date: Wed, 22 Nov 2006 14:07:25 -0500
From: "Robert Bruninga" <bruninga_at_usna.edu>
Subject: RE: [aprssig] APRS DF reporting
>>>I disagree, it is a very improtant issue.
>>>Bearing lines have an estimated length relative
>>>to the knowledge of the person doing the bearing
>>>line. That information must be included in
>
>... I disagree. The COSPAS/SARSAT hit gave a false
>impression of where the search area should be, and
>all of our a priori assumptions were wrong.
>I think I'd prefer to start with a generous
>estimate of the maximum possible range and use that.
I think we are in violent agreement. In the example you quote, seeing that
all the bearing linnes were not converging in your original estimated range
is exactly what APRS should have shown. It would have been obvious that
your initial assumptions were wrong and so simply extend the range
parameter.
A case of a wrong assupmption does not negate the value of having an
initial assumption in the first place.
>Ultimately, it should be up to the client software to limit
>the length of DF lines.
Yes, the SENDING stations software, so that the recepients all see the
*assumptions* under which the SENDER is searching...
>.... Still, I don't think it's ever safe to guess at
>the range. I've been on t-hunts where the transmitter
>was a tiny unit buried underground...
I'm not saying anything about "guessing". I am saying the searcher with
the DF unit that is putting information onto APRS has some "knowledge"
about the area where he is searching, either the terrain, or the scope of
the search, or his intuition. But *he* is still the -best_ source of
estimated bearing line length and that "knowledge" should be included in
the bearing line packet. That is why APRS includes the DF range in the
format.
If he is totally clueless, then he is well within his knowledge to put 500
miles if he wants. I'm just saying that if the information is known, then
it should be in there. If it is NOT known, then the sender still makes
that choice.
We do not want RECEIVEING plots to show anything other than what the sender
intended... Ever...
Bob, WB4APR
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Message: 3
Date: Thu, 23 Nov 2006 11:13:55 -0500
From: "Chris Bouck" <cbouck01_at_twcny.rr.com>
Subject: [aprssig] WinAPRS to work with an MFJ 1278 tnc
Does anyone know how to get WinAPRS to work with an MFJ 1278 tnc? I am
running Win 98SEand WinAPRS ver 2.75. I see stations on the screen, but
when I try to send a message, the tnc sends and radio seems to transmit,
but when I listen with another spare 2 meter rig on 144.390 - there is no
packet burst? What am I doing wrong? Any suggestions would be appreciated?
Please contact me at: cbouck01_at_twcny.rr.com
Thank you and 73
Christopher L. Bouck, KB4CMF
Past President, Ft Herkimer Amateur Radio Association, Inc.
Treasurer FHARA
Assistant Emergency Coordinator for Operations (ARES)
Official Emergency Station
SFC US Army / PO2 US Navy (Ret)
Director, Herkimer County Veterans' Service Agency
Accredited Representative for the American Legion, Vietnam Veterans of
America, and the VFW
_\|/
(o o)
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Message: 4
Date: Thu, 23 Nov 2006 08:44:04 -0800
From: "VE7GDH" <ve7gdh_at_rac.ca>
Subject: Re: [aprssig] WinAPRS to work with an MFJ 1278 tnc
Christopher KB4CMF wrote...
>but when I try to send a message, the tnc sends & radio seems
>to transmit, but when I listen with another spare 2 meter rig on
>144.390 - there is no packet burst? What am I doing wrong?
Do you mean that you aren't transmitting any tones, or that you aren't
being digipeated? Please reply to aprssig_at_lists.tapr.org.
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"
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