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ZL3AI > APRDIG 21.06.03 19:53l 263 Lines 9278 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Sunday, June 15, 2003.
1. Weather Object ?
2. Re: Weather Object ?
3. APRS in remote areas
4. Re: ProtoPath List - WinAPRS v2.61
5. Wxsvr Lonely
6. Re: Weather Object ?
7. Re: VOICE ALERT for Europe
8. Re: PIC accessory for Mobile APRS
9. Re: PIC accessory for Mobile APRS
10. import raw data
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Subject: Weather Object ?
From: "Dave Sloan" <desloan@earthlink.net>
Date: Sun, 15 Jun 2003 01:50:06 -0600
X-Message-Number: 1
Hello,
We had some sever weather here today. So, I decided to place a couple of
storms on my map. I gave them direction and speed. However 2 of them tracked
according to the speed and direction and the other two stayed stationary. I
couldn't see any difference in the four except for the start location and
the name. Any idea why two of my weather objects didn't move?
Tnx & 73,
Dave N0EOP
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Subject: Re: Weather Object ?
From: Bob Bruninga <bruninga@usna.edu>
Date: Sun, 15 Jun 2003 11:40:30 -0400 (EDT)
X-Message-Number: 2
Comments are valuable but useless unless you indicate what software is
transmitting the objects and what software is receiving the objects..
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Subject: APRS in remote areas
From: Bob Bruninga <bruninga@usna.edu>
Date: Sun, 15 Jun 2003 11:45:10 -0400 (EDT)
X-Message-Number: 3
I forward this to the SIG, because it is an important concept for
distant travelers:
---------- Forwarded message ----------
From: Bob Bruninga <bruninga@usna.edu>
Someone said:
>you can check my "Progress" as I trek to/through Alaska.
>... I'm sending updates every 30 minutes.
I dont know the details, but I would suggest that when an APRS traveler is
not in full coverage of the APRS system that he should send his posit at
least once every minute, if not more often. Two vehicles passing at 60
MPH only have about 2 minutes when they are within 5 miles simplex of each
other. Even beaconing at once every minute only gives you two or 3
chances to be heard by the other station.
With all the vagaries of propogation and other things that could cause the
other station to not hear a single packet, the statistics of being heard
with a once every 30 minute beacon are vanishingly small...
In 30 minutes, two passing stations can be 60 miles apart.
Dont worry about power either. Transmitting every minute is insignificant
as far as power is concerned. The average current for a D700 for example
just receiving is about 600 mA? The AVERAGE current including
transmitting at 50 watts one second once a minute only increases the
current by 1/60th of 8 amps or about 130 mA. Insignificant to the
receiver power...
Your best bet is to transmit via PCsat from midday to sunset. After
listening one day, you will hear PCsat on 144.39 and then if you remember
that time, you can remember that PCsat comes over exactly 1/2 hour earlier
every day and that there are passes 100 minutes before and 100 minutes
after as well... SO go to PCsat during those times.
ALl the rest of the time, beacon away on 144.39 once a minuite in case you
run into someone nearby on the ground...
If you are in a populated area, run CTCSS-100 so you will hear otehr Voice
Alert stations. If you are in the wilderness change to normal squelch so
that you will hear ANY packet station you may get near... Hopefully, they
also are beaconing once a minute to improve changes of finding each
other...
Just some thoughts...
de WB4APR@amsat.org, Bob
PCsat WEB page http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ: http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite http://ssdl.stanford.edu/mims/
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Subject: Re: ProtoPath List - WinAPRS v2.61
From: Glenn Wiebe <gswiebe@mts.net>
Date: Sun, 15 Jun 2003 10:46:12 -0500
X-Message-Number: 4
Werner, thanks for the tip.
73 de Glenn...VE4GN
Matt Werner wrote:
>
>I just read an interesting article yesterday referring to that (I
>believe)...
>
>http://web.usna.navy.mil/~bruninga/aprs/id-noid.txt
>
>73 - Matt
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Subject: Wxsvr Lonely
From: <kg5qd@wxsvr.net>
Date: Sun, 15 Jun 2003 12:36:40 -0400 (EDT)
X-Message-Number: 5
Hi All-
Murphy's Law still rules- I am on vacation until June 23rd. Left Wxsvr
running- it has been very stable for the last 3 or 4 weeks since the last
upgrade. Roger G4IDE released a new version of Ui-view with some Wxsvr
specific enhancements. It then crashed sometime Saturday due to lack of
attention from me I guess. It is back for the moment anyway. Could be
intermittant until I get back.
73 de kg5qd Dale
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Subject: Re: Weather Object ?
From: KC7ZRU - Tate <kc7zru@arrl.net>
Date: Sun, 15 Jun 2003 10:54:17 -0600
X-Message-Number: 6
Some one correct me if I'm mistaken, but aren't severe weather items
already insterted into the APRS-IS by Dale's servers? Instead of manually
creating these objects, again, maybe what's needed is a properly configured
I-gate?
If the NWS considers any weather event to be significant, they'll issue
information on it. Dale's servers take that info, parse it into APRS
objects and sends them on their way. This process is already automated.
Also - what with the variety of client software out there, each being a bit
different in how it creates and manages any objects, cluttering screens
with manually manipulated and possibley erronious information is of
marginal use to anyone. (Well, other than the one learning how to do it,
that is - maybe on a different freq?)
But then, my concern here assumes that these manually created objects are
geted to either RF or the APRS-IS.
Dave, to better answer your questions directly, share what client sofware
you're using (WinAPRS, xasitr, UI-VIEW, APRSA+, pocketAPRS, etc.) and an
example of the string you sent. Then, maybe, we can see why your objects
didn't move as expected.
73
--
"The Dungeon" online at http://go.to/kc7zru
Casper, WY | CARC Repeater
DN62tt | 146.940-
http://www.trib.com/~carc
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Subject: Re: VOICE ALERT for Europe
From: Henk de Groot <henk.de.groot@hetnet.nl>
Date: Sun, 15 Jun 2003 21:32:54 +0200
X-Message-Number: 7
At 10:39 13-6-03 -0400, Alex wrote:
>I see. The 2896000th harmonic of 50Hz is right on 144.800Mhz. Who
>would've thunk. And there are at least a 100 of 'em in an FM receiver's
>passband. Phew, I'm glad I don't live in Europe.
But 100 Hz is quite common! When you rectify a 50 Hz Sine wave through a
Graetz rectifier or a two diode double phase rectifier then you get a huge
100 Hz component:
<view with fixed-space font>
In:
__
/ \
/ \
/ \
/--------\--------/ 50 Hz
\ /
\ /
\__/
After double phase rectification:
__ __
/ \ / \
/ \ / \
/ \ / \
V--------V--------V 100 Hz
In the 50 Hz signal you have 1 peak, after rectification you have 2 peaks;
i.e. 100 Hz. Of course now capacitors and regulators should make this a
smooth DC voltage, so normally there should not be any hum or buzz on the
signal; when there is however, you can bet its 100 Hz and not 50 Hz:
Hum left on the signal:
____ ____
---/ \---/ \
------------------- DC with superimposed 100 Hz leftover
I have CTCSS at 100 Hz and in the North part of our country I experienced
that packet broke through, although I didn't find any evidence that this
was somebody with voice alert. The packets were too frequently and it
lasted over quite some distance; it looked more like a digi that emits 100
Hz toghether with its signal. So it does occur... Of course the best way is
not to change the CTCSS setting but fix those stations. I don't think you
get any 100 Hz directly from the power distribution system. That's the only
place were I have expericed false alerts, in other places 100 Hz CTCSS
works just fine.
Kind regards,
Henk.
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Subject: Re: PIC accessory for Mobile APRS
From: "Andrew McDade" <amcdade@senet.com.au>
Date: Sun, 15 Jun 2003 14:02:59 +0930
X-Message-Number: 8
Gday all,
Im curious to know whether someone has figured out the TMD700 control
command for outputting their own position data. All other commands are there
to accomplish what Bob is suggesting here except, perhaps ?, a way to output
the current location data. The other way of course is to have a seperate
data feed from the GPS to the pic chip. Not as neat though, but maybe the
only option.
73 .. Andrew .. VK5EX
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