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ZL3AI > APRDIG 14.02.04 23:47l 242 Lines 10712 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Thursday, February 12, 2004.
1. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
2. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
3. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
4. Why Is It? New WinDoze User
5. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
6. Re: VX-2R Tiny HT HF SSB?
7. Re: Why Is It? New WinDoze User
8. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
9. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
10. Re: Why Is It? New WinDoze User
11. telemetry 'timestamping'
12. Alinco DJ-S11, Tx Audio, PTT...
13. Re: Why Is It? New WinDoze User
14. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
15. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
16. Re: question about 'timestamping' with IGATEd trafficto APRS-IS
17. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
18. Re: question about 'timestamping' with IGATEd trafficto APRS-IS
19. APRS Time stamps
20. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
21. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
22. IC3SAT R.F. XMIT hang up problem
23. Re: question about 'timestamping' with IGATEd trafficto APRS-IS
24. Re: question about 'timestamping' with IGATEd trafficto APRS-IS
25. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
26. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
27. Re: Alinco DJ-S11, Tx Audio, PTT...
28. Re: Alinco DJ-S11, Tx Audio, PTT...
29. findU status
30. Re: APRS donations to ECHO
31. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
32. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
33. Re: question about 'timestamping' with IGATEd trafficto APRS-IS
34. Re: question about 'timestamping' with IGATEd traffic to APRS-IS
35. Re: TRACE in the FLOOD parameter???
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Subject: Re: question about 'timestamping' with IGATEd traffic to APRS-IS
From: James Washer <washer@trlp.com>
Date: Wed, 11 Feb 2004 20:59:48 -0800
X-Message-Number: 1
Scott... slow down.. We're all talking about the timestamp that shows up in
front of the packet when you grab them from findu.. I 'think' you are
referring to a timestamp embedded in the packet.. I'm willing to bet that
know one is 're-writing' those timestamps.. Your data integrity is fine.
- jim
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Subject: Re: question about 'timestamping' with IGATEd traffic to APRS-IS
From: "Scott Miller" <scott@3xf.com>
Date: Wed, 11 Feb 2004 21:05:45 -0800
X-Message-Number: 2
The way I understand what Steve's saying, functions like telemetry and
weather plotting are dependant on the server timestamp and not the 'actual'
timestamp - not the behavior I'd expect.
Jim (KB0THN) pointed out that home stations frequently transmit timestamps,
and I understand how seriously messed up most PC clocks are. I'd think a
better approach would be to strongly discourage the use of timestamps when
you're not sure of the time source's reliability. It's probably too late
for APRS, but I'll definitely give it some thought in the OpenTRAC spec.
Scott
N1VG
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Subject: Re: question about 'timestamping' with IGATEd traffic to APRS-IS
From: Jeff King <jeff@aerodata.net>
Date: Thu, 12 Feb 2004 00:33:39 -0500
X-Message-Number: 3
GPS has a accurate clock in it, so one could take literal timestamps from
mobile units, assuming of course said mobile unit is running OpenTRAC.
I never could understand the intense interest in tracking one's home...
--
Jeff King, jeff@aerodata.net on 02/12/2004
On Wed, 11 Feb 2004 21:05:45 -0800, Scott Miller wrote:
>Jim (KB0THN) pointed out that home stations frequently transmit
>timestamps, and I understand how seriously messed up most PC clocks
>are. I'd think a better approach would be to strongly discourage
>the use of timestamps when you're not sure of the time source's
>reliability. It's probably too late for APRS, but I'll definitely
>give it some thought in the OpenTRAC spec.
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Subject: Why Is It? New WinDoze User
From: "Matthew Stennett" <wa4tkg@iwon.com>
Date: Thu, 12 Feb 2004 00:41:17 -0500 (EST)
X-Message-Number: 4
I have recently come back to running a WinDoze based OS computer and find
every time I try to save a copy of WinAPRS 272 it is saved by the computer
in a WORD file, and NOT an UNZippablepable one? What is going on ? Can't
figure it out. Can't seem to locate a copy of Aladdin on this computer, but
that's a bit irrelevant (or IS it?), the file is always getting saved as a
Word file, right off the bat, I'm not doing anything to cause
that.........what's the deal? Daaaaaaaaaaaah?
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Subject: Re: question about 'timestamping' with IGATEd traffic to APRS-IS
From: "Scott Miller" <scott@3xf.com>
Date: Wed, 11 Feb 2004 21:47:59 -0800
X-Message-Number: 5
Even relatively static data has some relevance to situational awareness. I
just hope we can get some sort of mechanism in place to have the digi take
over the job of announcing it. Something that'll let you say, "hey, this is
my house, it'll be here for at least the next 3 hours", and the digi would
then retransmit it every net cycle time for the next 3 hours in the same
transmission with all the other houses and things in its area.
Now, set aside maybe five seconds at the top of every even-numbered minute
for these bursts and make the trackers smart enough to stay out of those
slots, and coordinate slots between adjacent digis, and you can present a
fair amount of static data with very low channel utilization and a low
chance of collisions.
Scott
N1VG
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Subject: Re: VX-2R Tiny HT HF SSB?
From: "James Lux" <aprssig@luxfamily.com>
Date: Wed, 11 Feb 2004 23:56:21
X-Message-Number: 6
Indeed, the synthesizer in the radio may be pretty crummy, BUT, there is a
technique you can use (although I doubt any of the current PSK31 type
programs use it). If you feed in that external pilot tone, which is very
stable and has good phase noise, you can use that as your reference in the
decoder, rather than the sampler in the sound card. Essentially, you
measure not only the received signal, but also the LO (and audio sampling
clock, which is effectively mixed with the LO).
Non-trivial, I grant you, but certainly possible.
Jim, W6RMK
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Subject: Re: Why Is It? New WinDoze User
From: "Stephen H. Smith" <WA8LMF2@aol.com>
Date: Thu, 12 Feb 2004 00:23:12 -0800
X-Message-Number: 7
Matthew Stennett wrote on 2/11/2004, 9:41 PM:
>I have recently come back to running a WinDoze based OS
>computer and find every time I try to save a copy of WinAPRS 272 it
>is saved by the computer in a WORD file, and NOT an UNZippablepable one?
Huh? None of this make any sense whatsoever... WWhat are you trying
to do? What do you mean by "save a copy".
Download a copy from a website and direct it to a specific location on
your drive?
Copy an existing installed and functioning program?
(You can't do this with installed Windows programs!!! You MUST use the
original install program to setup a new installation. Windows
installers place files in all sorts of places other than just the
program's own folder, add entries to the Windows registry file, place
..INI files in the main Windows system folder, and do other things that
will get left behind if you simply try to pick up and copy the as-built
installed program. Not to mention that many installers install programs
differently depending on what version of Windows the SETUP utility finds
itself waking up in! )
Versions of Windows before XP lack factory-provided archiving and
compression utilities. You need to download and install the third-party
WinZip archiver/compression utility from:
http://www.winzip.com
if it isn't already on the machine.
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff
http://members.aol.com/wa8lmf/aprs
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Subject: Re: question about 'timestamping' with IGATEd traffic to APRS-IS
From: Steve Dimse <k4hg@tapr.org>
Date: Thu, 12 Feb 2004 07:28:03 -0500
X-Message-Number: 8
On 2/11/04 at 5:59 PM Scott Miller <scott@3xf.com> sent:
>Say what? How do you figure that? When I transmit a timestamp it's because
>I want to know when that fix was taken, not when it managed to make its way
>into the network. For weather stations that don't have a GPS and are
>possibly relying on an internal RTC I can maybe understand it, but trackers
>have very accurate timestamps provided along with the position from the GPS.
And yet, even with most mobile stations, the GPS is not used to set the
computer's clock. Take a good look at the timestamps that appear on APRS,
using them would be a real nightmare.
>And even if we ARE talking about weather stations, what if I want to take
>readings at 2-minute intervals but only transmit them in a batch every 10
>minutes? You're saying that the timestamps are completely ignored and that
>they won't plot correctly? I can't see how it would ever be a good thing to
>second-guess information that's explicitly provided in the packet.
That is inconsistent with the charter of APRS, as a "real time tactical
system". Other than objects (where by definition old positions are
transmitted) if data appears on APRS, it is real time. The latency of the
APRS system has been measured on many occasions, it is on the order of a
few seconds, which is plenty accurate for the stuff that we do. That is the
reason why all new APRS formats have dropped timestamps, they turned out to
be worthless. I'm sure you'll do it differently on OpenTrak, feel free to
rant away, but that is how we do it in APRS. Real time data only...if you
want old data to appear on findU, there is a mechanism using web or email
interfaces to do so. Timestamps there matter, because the latency of email
can be (but often isn't) more than a few seconds.
Steve K4HG
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