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ZL3AI > APRDIG 15.05.04 20:47l 257 Lines 9453 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Apr 30, 3/6
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: digipeater naming conventions
From: Robbie - WA9INF <mwrobertson@comcast.net>
Date: Fri, 30 Apr 2004 08:25:40 -0500
X-Message-Number: 22
Hi Bob,
To what do you refer to "APRS is not a 24/7 system"?
Are you advocating that digipeaters and home station "RELAYs" _NOT_ be
there unless the is an "event" for our local users.. I would think you
would not have to annonce to an area, "Hey, turn on your home RELAYs, I
am driving thru your neighborhood!"
Sometimes it seems you make statements, that seem lacking in definitions
and needs more explaining.. Just like this post, it would not be
necessary if comments like this didn't happen.. With due respect Bob,
explain...
Robbie
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Subject: Re: d700
From: "Tim Cunningham" <tim_cunningham@mindspring.com>
Date: Fri, 30 Apr 2004 09:21:06 -0500
X-Message-Number: 23
Hey Guys,
I spoke with the owner at Gigaparts and he said, "...we haven't told anyone
they were discontinued. They have been on perpetual backorder from
Kenwood..."
Tim - N8DEU
Huntsville, Alabama
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Subject: APRS at the BirmingHamfest
From: "Tim Cunningham" <tim_cunningham@mindspring.com>
Date: Fri, 30 Apr 2004 09:32:48 -0500
X-Message-Number: 24
This weekend is the BirmingHamfest (May 1 & 2) at the Zamora Temple
Birmingham, Alabama.
GPS Locator: N33 Deg. 32 Min. 59 Sec. W86 Deg. 38 min. 57 Sec
Saturday 9:00am - 5:00pm
Sunday 9:00am - 4:00pm
Talk-in frequency is 146.88.
APRS Forum Saturday at 11:00am presented by Tim Cunningham - N8DEU. General
APRS discussion, using APRS as a weather node system to participate in the
Citizens Weather Observer Program, and APRS equipment requirements will be
discussed.
http://www.w4cue.com/fest.html
See you at the Fest.
Tim - N8DEU
Huntsville, Alabama
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Subject: UIview object transmission vs APRSdos
From: K3for@aol.com
Date: Fri, 30 Apr 2004 11:10:33 -0400
X-Message-Number: 25
We were planning on using UIview for our next scout event to keep track of
about 50 troops as they moved from place to place at a big camporee.
The plan was to simply have several laptops running UIview with a local map
and then as we learned of the movements of troops via FRS, Voice, D7's or
grapevine or 'whatever', a few APRS operators would click on the troop ICON
and move it to the new location.
This way all screens throughout the venue (maybe even WEB pages for the
event) would always be updated. Unfortunately, we discoverd that UIview
appears to perform a rudimentary and prohibitive transmission algorithm
like WinAPRS used that would make it impossible to do this on this scale
without total gridlock on the channel.
We abandoned UIview and went back to APRSdos, which nicely uses (I thought)
the original APRS "new-info-quickly/old-info-decays" algorithm. This
causes the movement of any object to quickly and reliably be updated on
every screen while older objects take up less and less air time.
In APRSdos, if you move an object, it is transmitted immediately, then 16
seconds later, then 32, then 64 then 2 minutes then 4 then 8 then 16,
etc... (if it has still not been moved since then). So in the 30 minutes
since that troop moved to its new station, only 9 packets were required...
yet, it had 4 chances to be delivered to everyone in the first 90 seconds.
Compare this to the simplistic fixed rate approach:
APRSdos will average 9 packets per 30 minute per troop or 0.004 of channel
capacity. With 50 troops, this is about 20% channel capacity and perfect
for the APRS ALOHA channel. (Theoretical 36% with CSMA) and allowing other
capacity for the buses and other moving GPS stations which do report every
minute...
Clients that use the fixed rate approach to give say 5 retries in 5 minutes
will require THREE-TIMES as many packets (one per minute for 30 minutes)
and will clog the channel.
Further, it appears that UIview transmits all of its objects at once. Even
if you set to say only every 3 minutes and each of the main PC's is
tracking 16 troops, then once every 3 minutes you get this minute long
burst of objects. An ALOHA channel where statistically everyone shares
the channel cannot afford this kind of bulk transmissions...
If anything in the above is inaccurate, or can be fixed, please let me
know.
Skip
K3FOR
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Subject: Re: Antenna Question (Slightly off topic)
From: Jeff King <jeff@aerodata.net>
Date: Fri, 30 Apr 2004 10:15:02 -0500 (CDT)
X-Message-Number: 26
Here is a clip from gateway in which it discusses this hybrid coupler:
Gateway Vol. 1 No. 24 August 1985
Published by:
ARRL
225 Main Street
Newington, CT 06111
203-666-1541
Editor:
Jeffrey W. Ward, K8KA
EASTNET NOTES
Tom Clark, W3IWI, is also operating a MailBox with both 145.05-MHz and
145.01-MHz inputs. Tom, however, is using the W0RLI GateWay software to
connect the two frequencies. To reduce the congestion that is beginning
to bother everyone on 145.01 MHz, all local users in Baltimore and
Washington D.C. have been encouraged to use the 145.05-MHz port. This
helps keep 145.01 MHz open for EASTNET traffic entering and leaving the
Washington area. The 145.05-MHz input is served by the W3GXT-5
(Baltimore) and W3VD-5 (Laurel/Columbia) digipeaters. The novel thing
about this installation is that the radios for the two ports are combined
using an RF-hybrid combiner to drive a single power amplifier and antenna.
--
Jeff King, jeff@aerodata.net on 04/30/2004
On Fri, 30 Apr 2004 02:04:44 -0400, Jeff King wrote:
>Back in the PBBS days I did exactly what you are trying to do (based
>on a design recommendation from w3iwi). I built a quadrature hybrid
>that allow me to feed two radios into one amp that drove one
>antenna. See:
>
>http://www.microwaves101.com/encyclopedia/Quadrature_couplers.cfm#branchline
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Subject: Re: digipeater naming conventions
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Fri, 30 Apr 2004 11:19:58 -0400
X-Message-Number: 27
>>>Robbie - WA9INF <mwrobertson@comcast.net> 4/30/04 9:25:40 AM >>>
Hi Bob,
>To what do you refer to "APRS is not a 24/7 system"?
Its design goal is to be real-time-responsive. The published net-cycle
time for everyone in a local event is to be updated in about 10 minutes of
everything that is going on. WHat I meant by the above is that latency's
of 30 minutes is fine for 24/7 systems that just kinda like to see what is
going on over a daily period. In that case a net cycle time of about 30
minutes lets more stuff on the map from greater distances that are not
moving much. But it should not be the diriving design goal of APRS.
>Are you advocating that digipeaters and home station
>"RELAYs" _NOT_ be there unless the is an "event"
>for our local users.. I would think you would not have to
>annonce to an area, "Hey, turn on your home RELAYs, I
>am driving thru your neighborhood!"
Sorry, I did not mean to imply that at all. In order for APRS to work WHEN
needed on short notice it must be running 24/7 with everyone up to speed
and trained. The only way to do that is to have it running 24/7..
Sorry for the confusion...
Bob
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Subject: 802.11x two serial ports.... 802.11 APRS ?
From: "K. Mark Caviezel" <kmcaviezel@yahoo.com>
Date: Fri, 30 Apr 2004 09:29:23 -0700 (PDT)
X-Message-Number: 28
Jeff:
cool links on the 802.11 modifications.
how about 802.11 APRS which sends position updates to findu just on 802.11?
Wireless is becoming more and more prevalent, I imagine a good number of
APRS hams spend a lot of time within 802.11 coverage.
- KMC ac0ak
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Subject: D7 Antenna mods
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Fri, 30 Apr 2004 12:51:36 -0400
X-Message-Number: 29
If you have dropped your D7 from the tower or kicked it across the concrete
floor with a big 19" whip on it and busted the antenna connector you may be
as surprised as I was how easy the connector is to replace.
After removing the obvious screws and separating the plastic cover its just
two phillips screws to remove the connector! No diging around in the guts
other than to unsolder the center pin.
I have put off this surgery for over a year until today when I needed this
D7. Wish I had done it long ago.
Of course, I dont have time to get a new connector but I'm just grinding
off the broken stub and soldering a piece of RG-58 to the flange and then
Ill have a nice robust dangle to a BNC which is what I use on the radio
most of the time anyway...
After soldering to the flange (on the work bench and outside the radio,
then to attach the Cable and Flange assembly is just the same two phillips
screws and a tack-solder of the center conductor to the board.
Anyway, just thought I'd pass it along.
Actually this HT will be mounted permanently in a briefcase and the antenna
pigtail goes to a BNC mounted on the top so that when the case is open and
laptop is in use, the full 19" whip then attaches there...
Bob
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