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ZL3AI > APRDIG 12.07.03 09:14l 308 Lines 12614 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Wednesday, July 09, 2003.
1. Re: hidden transmitter problems
2. APRS Spec
3. Re: hidden transmitter problems
4. Re: hidden transmitter problems
5. Re: hidden transmitter problems
6. Re: APRS Spec
7. Don't know how many people noticed this
8. Overlay on a D700?
9. Re: Don't know how many people noticed this
10. Re: Don't know how many people noticed this
11. Re: Don't know how many people noticed this
12. Re: APRS Spec
13. Re: Don't know how many people noticed this
14. Re: Overlay on a D700?
15. Initalization Files, Where 2 GET?
16. Re: Don't know how many people noticed this
17. APRS on PocketPC users?
18. Re: Initalization Files, Where 2 GET?
19. Re: APRS on PocketPC users?
20. Re: Don't know how many people noticed this
21. RE: Error in attempting to install PMAP30 into WinXP Pro
22. Re: Don't know how many people noticed this
23. FCS implementation in C?
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Subject: Re: hidden transmitter problems
From: "Robert Mahoney" <rgmahoney@ameritech.net>
Date: Wed, 9 Jul 2003 8:26:10
X-Message-Number: 1
Perhaps a better comparison would be to temporarily QSY the digi and mobile
xmtr to a quiet frequency, capture the data, and use that as the control
group?... Just thinking with my fingers. Not sure of the logistics
complexity on your end.
Bob
wb8cxn
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Subject: APRS Spec
From: "Eric Christensen" <kf4otn@earthlink.net>
Date: Wed, 9 Jul 2003 10:43:22 -0400
X-Message-Number: 2
I currently have the PDF version of the APRS Spec dated 29 August
2000 (aprs101.pdf)(Document Version 1.0.1). I know there have been
additions to the symbols in the APRS world and I'm sure there have
been other changes. Have these changes been updated in the Spec? If
so, where can I download the newest version of the Spec?
Thanks,
Eric KF4OTN
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Subject: Re: hidden transmitter problems
From: wes@johnston.net
Date: Wed, 09 Jul 2003 11:20:34 -0400 (EDT)
X-Message-Number: 3
Your suggestion for QSY is coming... kc4pl and I both have kpc4 dual port
TNCs (mine is due in the mail in the next few days). The plan is to set
them up on alternate RX frequencies and have then trend the number of lost
packets over time. The TNCs can digipeat normally on 144.39, but will also
listen to some obscure unused packet frequency. Honestly, the point to
this part of the exercise is to establish a baseline for later
improvements... like diversity reception in a digipeater and alternate
input frequencies....
While some may say I'm beating a dead horse here, I will conceed that there
are more reasons than simply hidden transmitters to keep a mobile station
out. I revamped my map from yesterday (
http://imscorporation.com//kd4rdb/hidden_tx_case1.gif )to include the
location of an IGATE station (n5cwh-2). That IGATE is at it's closest,
3000 feet from the route kc4pl takes. Based on a 1.1 miles / minute rate,
I guessed that kc4pl-9 would have transmitted once approaching the IGATE
and once departing from it, each about 4700 or 5000 feet from it. All
bridges in that section of i-26 are overpasses. Now can someone tell me
how you stop a 50w mobile from getting to a base station which is 4700 feet
away? Yes, I know the obvious answer is drop just one bit in the packet...
but really, what would it take to drop 1 bit when a station is s9+20db? I
just can't accept that picket fencing or flutter would attenuate a signal
that much. Multipath? good chance - esp if a trucker passed him at the
moment he transmitted. However, I think it is more likely that a nearby
base station didn't hear the mobile, thought the channel was clear, and
walked all over the top of kc4pl's mobile with 50w.
Wes
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Subject: Re: hidden transmitter problems
From: "Matt Werner" <kb0kqa@arrl.net>
Date: Wed, 9 Jul 2003 10:58:46 -0500
X-Message-Number: 4
As I see it now, there are a couple of variables to the problem that you
have presented. I can name probably the two largest - I'm sure others can
add to the list as well.
The first being signal strength into the digi from the mobile.
The second being "hidden transmitter(s)".
Why not measure the percentage of times that a fixed station that transmits
regularly gets into a digi or igate? If there are "hidden transmitters",
one would think that they affect every station, not just mobiles, correct?
The perentage of times that a fixed station gets in should drop as channel
activity picks up if it is due to hidden transmitters. That should mean
that it drops during the day when you have more mobiles on the move thus
more stations transmitting.
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Subject: Re: hidden transmitter problems
From: "Mark Fellhauer" <sparkfel@qwest.net>
Date: Wed, 09 Jul 2003 12:07:54 -0500
X-Message-Number: 5
At 10:20 AM 7/9/2003, wes@johnston.net wrote:
>Now can someone tell me how you stop a 50w mobile from
>getting to a base station which is 4700 feet away? Yes, I know the obvious
>answer is drop just one bit in the packet...
If you are that close to the digi, 50 watts and FM capture effect would
more than offset any hidden transmitter - so to me the obvious answer is
more than likely hardware or environment (excluding hidden APRS
transmitters).
That or the digi is being saturated by QRM from NON-HAM sources. This has
been a problem with the Sioux Falls Digi, which is across the street from a
regional hospital, only a few hundred feet away from the tallest Water
Tower in the region, that has a dozen or more commercial antennas on top of
it, including one for a broadcast FM radio station - Which BTW, can easily
trigger a frequency counter in my house... Plus we are a block from Sioux
Falls University which leases it's 200' tower out to several commercial
interests. I can hear pager intermod in my fillings around here -
That's why I wear the aluminum foil hat. :)
Mark
KC7BXS
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Subject: Re: APRS Spec
From: "Curt Mills, WE7U" <hacker@tc.fluke.com>
Date: Wed, 9 Jul 2003 10:21:26 -0700 (PDT)
X-Message-Number: 6
On Wed, 9 Jul 2003, Eric Christensen wrote:
>I currently have the PDF version of the APRS Spec dated 29 August
>2000 (aprs101.pdf)(Document Version 1.0.1). I know there have been
>additions to the symbols in the APRS world and I'm sure there have
>been other changes. Have these changes been updated in the Spec? If
>so, where can I download the newest version of the Spec?
You can't. That said, here's what you're looking for:
http://www.ew.usna.edu/~bruninga/aprs/errata.html
--
Curt Mills, WE7U hacker_NO_SPAM_@tc.fluke.com
Senior Methods Engineer/SysAdmin
"Lotto: A tax on people who are bad at math!"
"Windows: Microsoft's tax on computer illiterates!" -- WE7U
"The world DOES revolve around me: I picked the coordinate system!"
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Subject: Don't know how many people noticed this
From: "Mark Fellhauer" <sparkfel@qwest.net>
Date: Wed, 09 Jul 2003 13:27:40 -0500
X-Message-Number: 7
http://www.iaru.org/rel030703att3.html
Scroll Down to "Morse Code"
July 4th can once again be marked as Independence Day. :)
Mark
KC7BXS
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Subject: Overlay on a D700?
From: "Eric Christensen" <kf4otn@earthlink.net>
Date: Wed, 9 Jul 2003 15:21:14 -0400
X-Message-Number: 8
I have my D700 setup as an S-Gate for PCSat. Is there a way to setup
the D700 to put an "S" overlay on top of the diamond symbol?
Thanks,
Eric KF4OTN
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Subject: Re: Don't know how many people noticed this
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 9 Jul 2003 12:28:20 -0700
X-Message-Number: 9
But will the FCC eliminate the requirement now that it can?
I can't see it making much difference either way. How many new HF operators
are getting on the air these days? Would there really be more without the
code requirement? What's the incentive, with the 'net being so ubiquitous
and cheap? I just started reviewing the Tech question pool last night with
a couple of friends who have had enough of the FRS band, but they've got no
desire to work HF. I suspect most newly licensed operators are in the same
boat. And for those who get bitten by the radio bug, 5 wpm isn't much of an
obstacle.
Speaking of FRS, how bad does malicious interference have to get before the
FCC will get involved, and will they actually do anything? Seems like it's
close to unusable in some parts.
Scott
N1VG
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Subject: Re: Don't know how many people noticed this
From: "Sean \\The RIMBoy\\" <sean@rimboy.com>
Date: Wed, 9 Jul 2003 14:52:25 -0500 (CDT)
X-Message-Number: 10
On Wed, 9 Jul 2003, Scott Miller wrote:
>But will the FCC eliminate the requirement now that it can?
>
>I can't see it making much difference either way. How many new HF operators
>are getting on the air these days?
You're talking to at least one. Although I must admit having no desire
(at this time) to use code though. I'd rather not subject others to the
pain. If you meant getting on HF to do code then well, you're not talking
to one. Maybe some day I'll get into code, but at this point I'd rather
be able to carry on a discussion better than 5wpm or do APRS.
>Would there really be more without the code requirement?
I think so. I would have done it a lot sooner if the code requirement was
not there. So I could run an HF APRS station. Seriously though, I held
off for awhile because I did not want to learn the code. Likewise I
wanted to get a good grasp on what I was doing on the tech bands before
getting my HF privs and making a fool of myself. If that makes me bad so
be it. We all have to start somewhere and likewise, all have our
opinions. I won't slam people that like to do code, it's just not my cup
of tea.
>What's the incentive, with the 'net being so ubiquitous and cheap?
For HF or for code? I can honestly say the few QSO's I've had on HF have
been worth it. I've been excited making the contact and excited after the
end of the QSO. I'm sure it will wear off, but it's been fun the few
times I've been on.
>I just started reviewing the Tech question pool last night with
>acouple of friends who have had enough of the FRS band, but they've got no
>desire to work HF.
Give them time. I had no desire to do HF when I got my tech. However,
over time I warmed up to the idea and finally decided to persue it.
Either they'll want to go for HF (code be damned) or they won't. I
decided taking the time to learn the code was a hoop I could put myself
thru to improve my privs. At least they're going for their tech, which is
better than sitting around on the FRS or CB bands.
>I suspect most newly licensed operators are in the same
>boat. And for those who get bitten by the radio bug, 5 wpm isn't much of an
>obstacle.
No, it's not. However, the testing sessions maybe. Just a friendly
reminder to those that might be VE's, please be friendly to people wanting
to take the test or upgrade. At a testing session that shall remain
nameless they had no patience and were pretty terse in explaining the
rules of the testing session. However, the other sessions I've been in
(including when I passed my tech at Dayton) were overly friendly and were
genuinely excited that we passed. I felt sorry for those that did not
pass at the one session, I felt things were already too tense to begin
with and these guys did nothing to help the situation. (note, some of
these people may be future APRS users!). For some people a testing
session may be the first contact some people have with an amateur. I
would not have returned if the one session was my first time taking the
test... and upon passing wonder if I'd want to be associated.
Sean...
--
Believing I had supernatural powers, I slammed into a brick wall.
--Paul Simon
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
KG4NRC http://www.rimboy.com Your source for the crap you know you need.
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