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ZL3AI > APRDIG 29.09.03 18:11l 223 Lines 9568 Bytes #999 (0) @ WW
BID : 2017-ZL3AI
Read: GUEST
Subj: TAPR Digest, Sep 26, 2/7
Path: DB0FHN<DB0RGB<OE5XBL<OE2XOM<DB0PV<DB0MRW<DB0FOR<DB0SIF<DB0EA<DB0RES<
ON0AR<LU6DTS<VK3AVE<ZL2BAU<ZL3VML
Sent: 030928/1338Z @:ZL3VML.#80.NZL.OC #:9239 [Chch-NZ] FBB7.00i $:2017-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: OZ RADAR MAP Calibration
From: "Andrew Rich" <vk4tec@hotmail.com>
Date: Fri, 26 Sep 2003 18:12:24 +1000
X-Message-Number: 4
Can someone help me out with the co-ords of our local radar ?
I want to use the radar iamge as a backdrop.
http://mirror.bom.gov.au/products/IDR503.shtml
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Subject: APRS Then and Now [was: I guess we're going to agree...]
From: "Ev Tupis (W2EV)" <w2ev@arrl.net>
Date: Fri, 26 Sep 2003 06:45:16 -0400
X-Message-Number: 5
Bob Bruninga wrote:
>WIDEn-N is not modern. I conceived it in 1994. Back then IT WAS NEEDED
>because you had to have WIDE4-4 to even find 50 users. A LOT has happened
>since then:
>
> 1) IGates (and GLOBAL connectivity)
> 2) now 20,000 users, not just 500
> 3) We have some great WIDEn-N networks that cover vast areas.
>
>WIDEn-N is still the BEST WAY TO GO FOR LONG HAUL PACKETS in areas that
>can afford the load. We should capatilize on that and continue to make
>WIDEn-N do GREAT things for us. But conversly, where the network is
>OVERLOADED, turning off out-of area DX packets by simply disabling WIDEn-N
>digipeating in some digis is a tool that SYSOPS can use to get control otf
>their local networks and make them MORE RELIABLE for local traffic.
I happened to run across a graphic as I was cleaning out the datafiles on
my computer. I thought I'd share it with the group. It is non-scientific
in the most strict sense of the phrase, but quite an "interesting see".
Take a gander for yourself:
http://www.rochesterny.org/beaconet/temp/aprs1999-2003.htm
Ev Tupis, W2EV
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Subject: XASTIR and ImageMagick
From: "Andrew Rich" <vk4tec@hotmail.com>
Date: Fri, 26 Sep 2003 21:03:22 +1000
X-Message-Number: 6
Gents,
I have been having a few problems with XASTIR lately down to the fact I do
not have ImageMagick installed.
What do I need to do to make the two come together ?
Will I have to re-compile XASTIR ? I already have it running.
I tried to do a .geo file with URL http:// but i read it needs ImageMagick
I am bitting the bullet and installign both
Cheers Andy vk4tec
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Subject: Re: Part 2/2 -Re: Take Control - oh let's just go backwards
From: Henk de Groot <henk.de.groot@hetnet.nl>
Date: Fri, 26 Sep 2003 12:05:33 +0200
X-Message-Number: 7
Hello Jeff,
At 13:35 25-9-03 -0400, Jeff Thomas - KD4EVB wrote:
>dupe/looping issues. Yeap, RELAY,WIDE and RELAY,WIDE,WIDE is the solution,
>see below:
>
>MASKED-12>S9PV8Q,K8SCH-10*,WIDE,WIDE3-3 [09/13/2003
>01:17:50]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,W8MWO*,WIDE3-3 [09/13/2003
>01:17:51]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,AB4WS-10*,WIDE3-3 [09/13/2003
>01:17:52]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,W8MWO*,WIDE3-2 [09/13/2003
>01:17:53]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,W8MWO*,WIDE3-2 [09/13/2003
>01:17:53]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,KD4EVB-10*,WIDE3-3 [09/13/2003
>01:17:57]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,W8MWO*,WIDE3-2 [09/13/2003
>01:17:57]:<UI>:`p>]l!ck/"6\}masked
>MASKED-12>S9PV8Q,K8SCH-10,KF4INN-10*,WIDE3-2 [09/13/2003
>01:17:58]:<UI>:`p>]l!ck/"6\}masked
What could help a lot in this case is to employ digis whith long-term dupe
checking. I mean that it doesn't block duplicate packets for only 30
seconds as the Kantronics TNC do, but for example for 29 minutes. All the
packets you showed here are the same. When dupe checking is set to 29
minutes then all dynamic data from moving stations and stations that have
new information will be passed, but all static stations are effectively
changed to a 30 minute cycle rate. If W8MWO used this it would have saved
*at least* 3 packets instantly in this short example (and maybe more
because W8MWO might be the digi that made WIDE3-3 to become WIDE3-2 in some
of the packets). This is all without any loss of data since you aready had
the data and the new packets do no tell you anything new. If the station
moved you would have gotten an updated packet.
This is not just theory, we have tried it for 1/2 year on our local digi
and it worked very well. Before the changes hardly any mobile station got
through. As soon as we enabled this the number of visible mobile stations
rose dramatically. Besides that the QRG occupation sank below 18%.
Long term dupe checking in DIGI_NED doesn't affect messaging. Messaging
relies on duplicate packets so they get a special treatment. For the rest
it frees a lot of bandwidth by discriminating between static and dynamic
data. All static data is only passed every 30 minutes, dynamic data is not
affected at all. When you switch your APRS station on you will see the
moving stations very fast, the static houses and digipeaters are filled in
slowly over time. This way you can have much more than 50 stations on the
map without overloading the APRS QRG.
FUNDAMENTAL
-----------
The above example is another type of load control. Up to now the discussion
revolves arround the path and number of hops. But a statement that WIDE5-5
creates too much trafic is not valid on its own, it depends on how often a
packet with such a path is send. When a station with WIDE3-3 transmits with
a 1 minute rate, it creates a lot more traffic than a home station that
transmits once every 3 hours with WIDE5-5. 1200 baud APRS can sustain
WIDE5-5 or even WIDE7-7 DX packets if the repetition rate is kept low
enough.
Maybe some brains can be added to the client software to make a dependency
between repetition-rate and path specification. If one uses WIDE2-2 he is
allowed to transmit often, when he/she specifies WIDE7-7 then only a very
low rate can be selected and the faster rates are disabled. That way the
user has to make a tradeoff between visibility area and update frequency.
High frequency -> small area, Low frequency -> big area. I think users can
understand this tradeoff and are offered a clear choice.
Just my $0.02 to the discussion. Kind regrards,
Henk.
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Subject: Re: Part 2/2 -Re: Take Control - oh let's just go backwards
From: "Spider" <spider@rivcom.net>
Date: Fri, 26 Sep 2003 06:00:42 -0700
X-Message-Number: 8
From: "Henk de Groot" <henk.de.groot@hetnet.nl>
To: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Cc: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Sent: Friday, September 26, 2003 3:05 AM
Subject: [aprssig] Re: Part 2/2 -Re: Take Control - oh let's just go
backwards
>What could help a lot in this case is to employ digis whith long-term dupe
>checking. I mean that it doesn't block duplicate packets for only 30
>seconds as the Kantronics TNC do, but for example for 29 minutes. All the
>packets you showed here are the same. When dupe checking is set to 29
>minutes then all dynamic data from moving stations and stations that have
>new information will be passed, but all static stations are effectively
Hi Henk!
Please explain this more! How does setting a 29 minute dupe check fix a
problem that occurs within 30 seconds over xx% of time? If you log packets,
you see bursts of packets from stations that have reasonable settings.from
the various digi's that are local. I have three digi's that are very close
and for 1 packet someone sends, I might see 6 (not really counting). They
occur within 30 seconds of each other! So please explain how a 29 minute
dupe checker is going to solve this, please!
Also....Software issues. UI-VIEW comes with a 9 second default dupe check.
I've always recommended it be set at something high than 25 seconds. Mine
is set to 45 seconds.
Jim, WA6OFT
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Subject: WIDEn-N dynamic filtering...
From: Bob Bruninga <bruninga@usna.edu>
Date: Fri, 26 Sep 2003 09:08:06 -0400 (EDT)
X-Message-Number: 9
By the way, the disable-n-N routing option can be something you ONLY
use when a SAR or SKYWARN or other local event is activated. Nothing
wrong with letting the DX in the rest of the time, when local
reliability isnt important. I like seeing lots of stations as much as
anyone else... when only the grass is growing...
>Well, then you're probably right for around here (got 473 stations in the
>logs right now for 24 hours) and we're just screwed regardless of what I do
>huh? We're usually in the lower 300 range so I'd guess the band is up, oh
>boy kiss local reliability goodbye, the digi's TNC DCD light probably looks
>"stuck on" right now,..
Yep. If nothing important is going on, then leave WIDEn-N active so you
can see lots of DX stations. All I am saying is that disabling-n-N
routing is an instantaneous local OPTION that can be activated at any time
when you want to cut out DX QRM to improve local reliabilty.
If you do the calculations and don't need to reliably support the 16
mobiles I hypothesized in arriving at the 50-ALOHA circle, then the same
net can support as many as 150 home stations reliably. NOthing wrong with
that if you dont need to track local mobiles reliably at the same time..
But bottom line is that the channel is limited and can only support about
360 different packets reliably, bringing in more, just cuts reliablity at
the local level..
de WB4APR, Bob
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