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ZL3AI > APRDIG 03.10.03 09:38l 238 Lines 9240 Bytes #999 (0) @ WW
BID : 2062-ZL3AI
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Subj: TAPR Digest, Sep 30, 5/16
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<ON0AR<WB0TAX<N1UAN<ZL2BAU<ZL3VML
Sent: 031002/1402Z @:ZL3VML.#80.NZL.OC #:9559 [Chch-NZ] FBB7.00i $:2062-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Cheap GPS receivers / RS232 / Digitraveller
From: "Curt Mills, WE7U" <hacker@tc.fluke.com>
Date: Tue, 30 Sep 2003 09:24:12 -0700 (PDT)
X-Message-Number: 16
On Tue, 30 Sep 2003, Scott Miller wrote:
>>I cleaned out one local xx's whole stock of 2 of these. Quite the deal.
>
>I've scrounged up four myself so far. I think one store in town's got at
>least one left.
>
>>First thing I did when I got mine home was crack it open. You can see
>where,
>
>Bah. I had mine open before I was out of the parking lot. =]
You guys are... are.... HAMS!!!
I bought out the stock of 2 at the nearest one yesterday and asked them to
collect four more from nearby stores. Paid for all six on the spot.
I can replace the TO-92 regulator on a TinyTrack with a TO-220 regulator
and power the GPS off that. I've done that before and used it with a
Trimble SV6 board, but these Digitraveler GPS's use a lot less power!
That's an advantage even if they are physically quite a bit larger. The
specs appear to say they use 75mA.
--
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: Re: Cheap GPS receivers / RS232 / Digitraveller
From: "J. Lance Cotton" <joe@lightningflash.net>
Date: Tue, 30 Sep 2003 11:36:25 -0500
X-Message-Number: 17
Yes, the software will work on Palms, but the cable is only for the latest
m-series models (m125, etc.)
-Lance KJ5O
--
J. Lance Cotton, KJ5O
http://map.findu.com/kj5o-14
joe@lightningflash.net
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Subject: Re: Digipeater Duplicate Checking is broke
From: "Scott Miller" <scott@opentrac.org>
Date: Tue, 30 Sep 2003 09:56:37 -0700
X-Message-Number: 18
Ok, here's a physics problem for the list... given two digipeaters 20 miles
apart, both at the same HAAT, with the same gain and power output, how
large is the zone between them where the difference in amplitude between
the two signals is less than 2 dB? In other words, how big is the dead
zone where receivers won't decode either digipeated packet?
Scott
N1VG
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Subject: Re: Digipeater Duplicate Checking is broke
From: wes@johnston.net
Date: Tue, 30 Sep 2003 13:23:47 -0400 (EDT)
X-Message-Number: 19
Don't you mean 20db? I thought that was the threshold for FM capture to
work properly? Gosh, if we could just synch the two digi's down to the bit
level.... just like pagers do... THEN we'd have a single transmitter system
which would work.... Let's see... there's a local TV station which could
be used for synch or GPS 1 PPS signal.
Although I like the idea of fracticide, I have found recently with one
digipeater (ie one copy of each packet), if I have any flutter in my
mobile, I don't decode a packet. At least with two digipeaters, I double
my odds of getting a copy of a given packet.
Wes
ham callsign: kd4rdb
find me: http://wesvan.zapto.org
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Subject: Re: Take Control of your DIGI part 4
From: "Dick Stanich" <dick@kb7zva.com>
Date: Tue, 30 Sep 2003 12:49:10
X-Message-Number: 20
>>Ithink DIGI's should only run ONE (1) of the three common 'names' (being
>>RELAY or WIDE or TRACE).
>>In other words, in your local network, if you are going to be a WIDE, then
>>be a WIDE and do not be a RELAY. If you are a RELAY, then you are not a
>>WIDE, so don't be one. Define them. Use them to take advantage of
>>coverage!
>
>Ah, but if a mobile uses the generic path of RELAY,XXXXX and he is
>driving near one of your WIDE only digis, then he is out of the network
>even though he is under a digi. That is why all digis have to do
>RELAY...
Bob is correct, for good reason. If the mobile isn't being digipeated on
RELAY,XXXXX what choices does the operator have. Will he start to modify
his path trying to reach out? You bet. That path didn't work... so I'll try
WIDE5-5 and take advantage of better coverage. That thinking has gotten us
into trouble, because we are actually causing users to make wrong
alternative decisions.
UIDIGI ON RELAY,WIDE,TRACE,XXXXX should be universal for all digis
everywhere, along all major traffic corridors. Locally, small low-level
digis can fill in the gaps as needed. Hopefully, at the center of all this
is a full-service Igate, to take care of cell to cell traffic handling.
But, that's another story :)
Dick
APRSWest
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Subject: ***New*** TRACEn-N (LANn-N) Paradigm
From: Bob Bruninga <bruninga@usna.edu>
Date: Tue, 30 Sep 2003 13:52:02 -0400 (EDT)
X-Message-Number: 21
WHile further analyzing how we get to the new n-N paradigm, I have a
MODIFIED proposal for LANn-N operations that solves ALL problems...
Remember my LANn-N concept gets packets to X surrounding digis, but only
generates X copies if there are X LANn-N digis. Not hudnreds of flooding
QRM copies. AND this is independend ot N. It is only dependent on the
size of the X digis LAN. This is under local SYSOP control.
FOr the size and density of our 1200 baud system, it is doubtful that
anything more than LAN3-3 could ever be used anyway.
SO, CONSIDER THIS:
**** SET UP YOUR LANn-N network with the UITRACE parameter NOT the
UIFLOOD parameter!!!!!
With the UITRACE implementing of your LANn-N, (instead of UIFLOOD) now you
do NOT have to MIX an initial WIDE,LANn-N which does propagate some dupes.
But you can use just the basic LAN3-3 path which will arrive at EVERY
digipeater in your X digi LANn-N with NO dupes and with full traceablity.
and injection point identificaiton. Yes, the path arrives as
DIGI1,DIGI2,DIGI3, but that is a very SMALL price to pay for all the
advantages!!!
1) A MULTI fold increase in the usable bandwidth of your LAN
(every packet is designed to hit about X surrounding digis
(instead of 21 to 36 with generic FLOODn-N (3 hops))
2) A MULTI-SQUARED reduction in QRM (from all directions)
3) A MULTI-SQUARED imporvement in the reliablity of your network.
4) Universal operation everywhere using ONE universal setting
(starting with RELAY and WIDE)
5) FULL PATH TRACING of every packet (via callsign substitution)
(or the UITRACE feature of LANn-N when N is 3 or greater)
6) Point of injection identification of EVERY packet
7) Better performance of long haul WIDEn-N generic traffic through areas
that can support it. And no stigma attached to such use.
8) Automatic QRM limiting for LANn-N routing to only X copies for X
digipeaters independent of N.
9) Full length LINKn-N routing with only worst case 7 copies instead
of 100 to 200 copies.
SO, that is a modification of the ***NEW*** WIDEn-N paradigm:
1) TUrn off WIDEn-N in all areas that cannot afford to be seeing
anythign beyond 3 hops without flooding the network
2) Change the UIFLOOD to set up long LINKn-N sustems where needed
3) use the UITRACE parameter to set up area LANn-N networks that guarantee
delivery to all X digipeaters in the LANn-N area, without dupes but
with full tracing. (but this will never be mroe than about 3 calls)...
4) Notice that a SINGLE digi can now BOTH support LINKn-N, and LANn-N AND
is no longer vulnerable to WIDEn-N flooding from out of area!!!
Wow. That is the best of all worlds and we can do it TODAY!
de WB4APR
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Subject: Re: Nice points Tim & some questions for the gang
From: Bob Bruninga <bruninga@usna.edu>
Date: Tue, 30 Sep 2003 14:10:06 -0400 (EDT)
X-Message-Number: 22
On Tue, 30 Sep 2003, Jeff Thomas - KD4EVB wrote:
>With multiple monitoring points setup across the area, collect data on
>what happens when:
>
>1. You run a pure WIDEn-n path of WIDE5-5...... versus
>2. You run a path of WIDE,WIDE,WIDE,WIDE,WIDE
Duh, we all know the result. It is a TOTAL MESS. Doesnt anyone get it?
Our networks can no longer afford to have everyone's single packets FLOOD
the network in ALL directions with HUNDREDS of copies!
>4. Make the results and data available for any/all to look over.
What a waste of time. Abandon the FLOOD mentality and lets go fix the
network. FLOODING no matter how efficinet you make it, is still FLOODING
a 1200 baud LOCAL channel with too much stuff that it cannot possibly
support...
Decide what your local ALOHA area is, (SOmewhre between 50 to 100 users
depending on the number of Mobiles you need to support).
THen ABANDON the old UIFLOOD WIDEN-N concept and change it to support long
LINKn-N linear paths and implemente AREA LANn-N using the UITRACE...
parameter. (and make sure you still support RELAY and WIDE for locals)
and ALL problems are solved.
But you must abandon the imppossible FLOOD concept.. It cannot work on a
1200 baud channel shared by thousands of users...
de WB4APR, Bob
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