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ZL3AI > APRDIG 07.04.07 06:04l 251 Lines 9030 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 34 #4, 3/3
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To : APRDIG@WW
Message: 16
Date: Thu, 5 Apr 2007 10:13:19 -0400
From: "Robert Bruninga" <bruninga@usna.edu>
Subject: [aprssig] New Orleans, Operating Freqs and spam
>The sad reality is... This is why not a single solitary
>APRS message was sent from Downtown New Orleans over
>the sole surviving Digi during the Aftermath of
>Hurricane Katrina. And that Digi was up at like 550ft!
Yes, I was so very impressed that in the aftermath, there was a digi,
covering the entire area with a PHG at 550 feet right in the middle of New
Orleans, but I don't think APRS was used to its full potential. When I
made suggestions as to a few simple efforts that would improve the
situation on this SIG, I was told to butt-out. Ideas were:
1) It was a WIDE only digi. Get word out to use WIDE
2) From Mobile or other areas with internet, point a BEAM towards new
orleans and put a temp digi with WIDE to link Bew Orleans back to the
internet
3) Tell all mobiles to activate their mobile TNC's as digis...
I think after a few days we did begin to see a few mobiles, but I don't
think I saw more than 3 or so. But then I could only watch via the
internet from 1500 miles away. I wonder if there was ever an overall
assessment published?
But one initiative that came out of that was my focus on getting EVERYONE
to include their operating voice frequency in their beacons, and for voice
repeater frequencies to be beaconed locally by digis so that visiting
mobiles could be informed as to operating frequencies. I wanted FINDU to
begin parsing Frequency so that anyone at any time could see not only where
HAM asssets were but how to contact them as well.
Llittle progress has been made. I drove from MD to PA, last week and only
2 voice repeatere receommendations showed up on my screen. A third was
there, but it has been there for years and is a UHF repeater that is sent
out via 2 or 3 hops to 4 states, but cannot be worked except within 10
miles. So not only do we have to get the local direct beacons on the air,
but we have to get these 90% useless SPAM frequencies off the air.
So much to do..
WB4APR, Bob
------------------------------
Message: 17
Date: Thu, 5 Apr 2007 10:25:45 -0400
From: "C J Rohrer Jr" <nr3u@aol.com>
Subject: Re: [aprssig] Deviation meters
Scott and List, Some years ago I purchased a deviation meter and it has
been most helpful, especially when setting up 9600 baud.
I purchased the unit from 'RF Applications, Inc', of 7345 Production Drive
in Mentor, Ohio 44060
It's model number is 33D20000
A series of LEDs are used. I don't remember the cost but I believe it was
not too expensive. A very good unit.
Best, Clem -nr3u
------------------------------
Message: 18
Date: Thu, 5 Apr 2007 07:40:11 -0700
From: "Keith VE7GDH" <ve7gdh@rac.ca>
Subject: Re: [aprssig] New Orleans, Operating Freqs and spam
Bob WB4APR wrote...
>Yes, I was so very impressed that in the aftermath, there was a
>digi, covering the entire area with a PHG at 550 feet right in
>the middle of New Orleans, but I don't think APRS was used to
>its full potential. When I made suggestions as to a few simple
>efforts that would improve the situation on this SIG, I was told
>to butt-out... 1) It was a WIDE only digi...
www.findu.com/cgi-bin/map-near.cgi?lat=30.0&lon=-90.0&cnt=50
Has that digi been updated yet? It would be nice to think that it and other
digis in the area had adopted the "new" settings both for everyday use and
to make them more compatible with other assets from the outside when they
arrive to help if there is a next time.
73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"
------------------------------
Message: 19
Date: Thu, 05 Apr 2007 10:52:20 -0400
From: John <johnk.mchugh@att.net>
Subject: Re: [aprssig] Deviation meters
Alan P. Biddle wrote:
>Scott,
>
>Back in the Dark Ages, about 15 years ago or so, TAPR produced a very nice
>deviation meter kit.
Alan et al,
Back in the Darker Ages we did it mathmatically with Bezzel Functions.
For those that don't know about this it is very simple to set the
deviation using an audio tone applied to the mike jack and a second
selective radio/receiver.
Mr. Bezzel proved, mathmatically, that there is a relationship between
modulation index and carrier on FM and PM radios. The ARRL Handbooks of
the late 90's show the graphs of Bezzel functions (on page 12.7 in my
1997 version)
..
The technique is to set the radio you want to set the mod on to a
frequency. Then with a second radio that has narrow selectivity (IC 706,
FT 100 or similar set to CW) monitor the carrier from the first radio.
You can also use a VHF/UHF down converter and an HF radio to monitor it
Set the audio generator to 2khz, then turn up the deviation control
slowly from zero until you hear the carrier null out. You then have the
deviation set to 4.8KHz. I've used this method many times to set radios.
The Bezzel function for the first carrier null is 2.405. The formula is
(Required Dev/ 2.405). So if you want to set the deviation to 3.5KHz,
use an audio tone of 3.5/2.405 or 1.455KHz. Oh, you don't have a
1.455KHz tone, then use the mark tone from a KAM, usually 1600Hz on HF.
There must be software that will produce variable audio tones from a
sound card, anyone know of such a program?
John
--
John Mc Hugh, K4AG
Coordinator for Amateur Radio
National Hurricane Center, WX4NHC
Home page:- http://www.wx4nhc.org
------------------------------
Message: 20
Date: Thu, 05 Apr 2007 09:29:57 -0700
From: "Stephen H. Smith" <wa8lmf2@aol.com>
Subject: Re: [aprssig] Deviation meters
johnk.mchugh@att.net wrote:
>The Bezzel function for the first carrier null is 2.405. The formula
>is (Required Dev/ 2.405). So if you want to set the deviation to
>3.5KHz, use an audio tone of 3.5/2.405 or 1.455KHz. Oh, you don't
>have a 1.455KHz tone, then use the mark tone from a KAM, usually
>1600Hz on HF. There must be software that will produce variable audio
>tones from a sound card, anyone know of such a program?
>
>John
The freeware utility bundle "Wavetools" on my web site downloads page
will do this.
It bundles 4 applications that use the sound card: an audio function
generator, an audio level (a.k.a. "V.U.) meter, a dual trace scope and
an audio spectrum analyzer.
Go to < http://wa8lmf.com/miscinfo > and look for the file
"Wavetools.exe" near the bottom of the list.
By the way, it's Bessel , not Bezzel . Incidentally, the traditional
RTTY mark tone of 2125 Hz produces a Bessel null at 5.1 KHz deviation.
--
Stephen H. Smith wa8lmf (at) aol.com
EchoLink Node: 14400 [Think bottom of the 2M band]
Home Page: http://wa8lmf.com --OR-- http://wa8lmf.net
NEW! World Digipeater Map
http://wa8lmf.net/APRSmaps
JavAPRS Filter Port 14580 Guide
http://wa8lmf.net/aprs/JAVaprsFilters.htm
"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths
Updated "Rev H" APRS http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:
------------------------------
Message: 21
Date: Thu, 5 Apr 2007 11:44:08 -0500
From: "Alan P. Biddle" <APBIDDLE@UNITED.NET>
Subject: RE: [aprssig] Deviation meters
John,
Finding the zeroes in the Bessel function is of course the way it has been
done for years. However, lots of people ask "Duh, what's a Bessel
Function?" And having done both, a good deviation meter is easier. ;)
Alan
WA4SCA
------------------------------
Message: 22
Date: Thu, 5 Apr 2007 09:49:17 -0700
From: "Bill Vodall WA7NWP" <wa7nwp@gmail.com>
Subject: Re: [aprssig] New Orleans, Operating Freqs and spam
>>The sad reality is... This is why not a single solitary
>>APRS message was sent from Downtown New Orleans over
>>the sole surviving Digi during the Aftermath of
We in the Western Washington region had a small adventure last fall.
Nothing like Katrina but 4 nights of huddling around the fireplace with no
commercial electricity does give a person time to reflect on the state of
the network and their personal backup communications capabilities.
It was a bit of an eye opener.
My conclusion was that I wanted a full time, full function "tactical" APRS
station and fill in digipeater with indefinite backup power. Sure all the
legacy packet, TCP/Ip and Winlink2k gizmos will be handy but for the core
basic communications -- APRS will work the best.
Real soon now - a custom APRSDOS will be running full time on the old 486
laptop which will be powered off a 12V system with backup from a deep cycle
battery. The battery will be charged with a RigMountain PG40S charger from
the mains in addition to either solar and an extension cord to a soon to be
purchased Honda EU2000i generator.
charger - http://www.westmountainradio.com/rigrunner/pg40s.htm
73
Bill - WA7NWP
------------------------------
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