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ZL3AI > APRDIG 26.10.06 06:36l 222 Lines 9050 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 28 #10, 1/4
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Sent: 061026/0532Z @:ZL2BAU.#87.NZL.OC #:11299 [Waimate] $:8874-ZL3AI
From: ZL3AI@ZL2BAU.#87.NZL.OC
To : APRDIG@WW
Today's Topics:
1. Re: 9600b UHF APRS IS THE FUTURE OF APRS (Gregg Wonderly)
2. Re: 9600b UHF APRS IS THE FUTURE OF APRS (wa7nwp_at_jnos.org)
3. RE: 9600b UHF APRS IS THE FUTURE OF APRS (Andrew Rich)
4. RE: 9600b UHF APRS IS THE FUTURE OF APRS (scott_at_opentrac.org)
5. Re: 9600b UHF APRS IS THE FUTURE OF APRS (Bob Bruninga )
6. Re: 9600b UHF APRS IS THE FUTURE OF APRS (Patrick Green)
7. Re: 9600b UHF APRS IS THE FUTURE OF APRS (Gregg Wonderly)
8. Mic-E STATUS refresh and bad software? (Bob Bruninga )
9. RE: Mic-E STATUS refresh and bad software? (scott_at_opentrac.org)
10. Re: ARISS (Rich Walrath)
11. Re: ARISS (A.J. Farmer (AJ3U))
12. List of APRS web services (scott_at_opentrac.org)
13. Re: ARISS (Bob Bruninga )
14. Re: List of APRS web services (Stephen H. Smith)
15. RE: Mic-E STATUS refresh and bad software? (Bob Bruninga )
16. RE: List of APRS web services (scott_at_opentrac.org)
17. RE: Mic-E STATUS refresh and bad software? (scott_at_opentrac.org)
18. Re: List of APRS web services (Tyler Allison)
19. Marathon support with APRS (William McKeehan)
20. Maxon data radios (scott_at_opentrac.org)
21. Re: Marathon support with APRS (Jason Rausch)
22. Re: Maxon data radios (Lance Cotton)
23. Re: Marathon support with APRS (Bob Bruninga )
24. Re: Maxon data radios (Stephen H. Smith)
25. Re: 9600b UHF APRS IS THE FUTURE OF APRS (Joe Della Barba)
26. RE: Maxon data radios (Steve)
27. Low band APRS (was Re: 9600b UHF APRS IS THE FUTURE OF APRS)(Paul Zawada)
28. Re: Maxon data radios (Tyson S.)
29. RE: Maxon data radios (scott_at_opentrac.org)
30. Re: Maxon data radios (Stephen H. Smith)
31. RE: Maxon data radios (Andrew Rich)
32. RE: Maxon data radios (Andrew Rich)
33. Re: Maxon data radios (Ray Wells)
34. RE: 9600b UHF APRS IS THE FUTURE OF APRS (Dave Baxter)
35. RE: 9600b UHF APRS IS THE FUTURE OF APRS (Andrew Rich)
36. Re: Mic-E STATUS refresh and bad software? (Curt, WE7U)
37. RE: 9600b UHF APRS IS THE FUTURE OF APRS (Sean Jewett)
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Message: 1
Date: Mon, 09 Oct 2006 12:28:32 -0500
From: Gregg Wonderly <gregg_at_wonderly.org>
Subject: Re: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
Joel Maslak wrote:
>It's not the coverage that's the problem, it's the number of users in
>the collision domain and the size of the aloha circle vs. digipeater
>location and user paths.
Not to be picky, because you did qualify that statement, but it is exactly
the coverage that increases the number of users and the size of the aloha
circle. So, a system which can cover less area (at reasonable HAAT given
the expected coverage area), will have a better performance margin from my
perspective.
Gregg Wonderly
W5GGW
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Message: 2
Date: Mon, 9 Oct 2006 12:32:07 -0500 (CDT)
From: wa7nwp_at_jnos.org
Subject: Re: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
>>It's not the coverage that's the problem, it's the number of users in
>>the collision domain and the size of the aloha circle vs. digipeater
>>location and user paths.
>So, a system which can cover less area (at reasonable HAAT given the expected
>coverage area), will have a better performance margin from my perspective.
Don't forget "packet time" is also part of the equation. A 9600 baud
network with packets 1/4 the size of a 1200 baud network can handle 4X
(give or take) the number of users in its Aloha circle.
Bill - WA7NWP
------------------------------
Message: 3
Date: Tue, 10 Oct 2006 03:34:49 +1000
From: "Andrew Rich" <vk4tec_at_tech-software.net>
Subject: RE: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
Why stop there ?
Aircraft use PPM at a 1Mb rate and can send positions in 112us at a 1/2
second rate.
Just need some smart ham radio operators to try
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec_at_tech-software.net <mailto:vk4tec_at_tech-software.net>
web: http://www.tech-software.net
Brisbane AUSTRALIA
-----Original Message-----
From: Gregg Wonderly [mailto:gregg_at_wonderly.org]
>Joel Maslak wrote:
>>It's not the coverage that's the problem, it's the number of users in
>>the collision domain and the size of the aloha circle vs. digipeater
>>location and user paths.
>
>Not to be picky, because you did qualify that statement, but it is exactly
>the coverage that increases the number of users and the size of the aloha
>circle. So, a system which can cover less area (at reasonable HAAT given
>the expected coverage area), will have a better performance margin from my
>perspective.
>
>Gregg Wonderly
>W5GGW
------------------------------
Message: 4
Date: Mon, 9 Oct 2006 10:50:18 -0700
From: <scott_at_opentrac.org>
Subject: RE: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
It's not all about going faster. Data rate alone is never going to be the
way to fix the system.
I'm also not convinced that a cellular style system is ever going to
succeed. Hams are good at developing high elevation repeater sites, and
it's much easier to build and manage a few large systems than a bunch of
small ones that might need to be in inconvenient places. Home-based
systems are another matter, but we'll never have them in all the right
places.
Run timeslotting with 200 msec slots, have digis provide at least some
loose coordination of slot assignment (overlapping coverage areas and odd
band openings complicate assignment schemes) and you could have hundreds of
stations on a single channel with a cycle time of a few minutes. Now, add
a multichannel receiver at the digi site (maybe gnuradio based) and you can
multiply that capacity by the number of channels available. The dedicated
downlink from the digi can run at 9600 with no collisions, so you could
still get all of the local traffic by listening to a single frequency.
Baud rate is NOT the primary limiting factor in APRS. We could probably
increase our channel capacity by 50% if we could just get everyone to set a
reasonable txdelay and stop using long comments on every packet. I see way
too many short Mic-E packets with a 30-character comment tacked on to every
position report. Not to mention D700's with half-second txdelays...
Scott
N1VG
------------------------------
Message: 5
Date: Mon, 9 Oct 2006 13:57:15 -0400 (EDT)
From: "Bob Bruninga " <bruninga_at_usna.edu>
Subject: Re: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
>>It's not the coverage that's the problem, it's the
>>number of users in the collision domain and the
>>size of the aloha circle vs. digipeater location...
>
>Don't forget "packet time" is also part of the equation.
>A 9600 baud network with packets 1/4 the size of a 1200
>baud network can handle 4X the number of users in its
>Aloha circle.
BUT, in order to make 9600 baud work at UHF, you first have to make up a 9dB
RF link penalty, and a few dB decoding penalty. This requires you to have
to install 4 times as many digipeaters for the SAME performance.
Now, once you have installed 4 TIMES the number of digis, you now have much
smaller CELLS and can stuff in 16 times as many users. BUT WITH THE
DENSITY OF APRS AND HAM USERS, there just arent that many users to require
this tremendous effort.
Again, I am not opposed and I welcome the effort if people want to do it,
but to me, the effort far outweighs any benefit unless somehow we get 100%
of hams to routinely run APRS so that APRS can become what it was intended
to do.
That is, to keep an APRS user fully informed of EVERYTHING in HAM radio
that is going on around him. This "informed" process is simply a single
packet in most cases of a position, or a status of what is happening in his
local VHF range.
Bob, Wb4APR
------------------------------
Message: 6
Date: Mon, 9 Oct 2006 12:55:16 -0500
From: "Patrick Green" <pagreen_at_gmail.com>
Subject: Re: [aprssig] 9600b UHF APRS IS THE FUTURE OF APRS
I operated 9600 on UHF for a short time along side the VHF digi currently
running and the performance was disappointing. I have a problem at that
site with long runs of feedline and can't keep the loss figures managable.
VHF is more forgiving. While in opation, I had to fish for a spot most of
the time while the system was running. It was running a Kantronics D4-10
running 10 watts on 430.55 to a 6 dbd omni at 80 feet. The 200 foot run of
feedline (90 feet of 7/8" heliax and 110 feet of RG-214U) made for some
dismal loss figures. Compound that with the fact that 430.55 is away from
where the antenna was cut for (448) and the D7A probably isn't optimized to
receive at that end of the range. When mobile, I could get in as long as I
was 4 miles of less from the station. Stationary, I could get in up to 8
miles or so away. Now compare that to the 2m system which has a 5.25dbd
gain antenna cut for 146.52 with 200 feet of RG-214U at the same height, I
can get into it from 8 to 9 miles away moving and as far as 20 miles away
stationary with the same D7A. Just thought I'd pass this along.
73 de Pat --- KA9SCF
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