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[aprssig] More digis are changing to the new paradigm

Brian Webster bwebster at wirelessmapping.com
Tue Jul 5 02:32:52 UTC 2005


Earl,
	I don't normally post on this topic but feel compelled to do so. At the
risk of offending you and your area aprs congestion, if people around you
were to use more extensive paths than wide2-2, and they are truly that far
away from you that means they are either on the West Coast (where there is a
congestion problem) or farther East say Denver area or Texas areas. If they
were to hop out more than two hops it goes in every direction not just to
the non-congested areas of New Mexico (and yes I have traveled there and
know how isolated you are). There is just no way possible for people to use
long paths so you can see them without hammering a metro area with
unnecessary packets. How do I know this? I have long suspected our local
digi here in the middle of rural NY (read dairy farm country and hills
compared to your mountains) was getting clobbered with collisions from other
wide digis. Our local APRS traffic is very light. This past week I changed
out our old digi TheNet chip to a UI-digi chip and started running the new
wide n rules. Now I can actually see how bad it was. In just two hops I can
have a packet on the outskirts of Boston to the East, almost at the border
of Ohio to the West, and certainly within earshot of Philly to the South.
This is with only two hops. The problem Bob is fixing is not isolated to his
area. It is everywhere but because of collisions in a UI non-connected
packet world, none of us can see it unless we park ourselves at the digi
sites to try and decode all the packets. Our site is not a super high
location but is on a good tower site. I am sure most APRS Wide digi's are as
well.
	Earl I respect you and your contributions to this list but I just have to
disagree with you on this one. If you really need to see more action,
connect to the net. You simply can't put all this traffic in a 1200 baud
network with no real routing and expect it to go far. I have worked with
many commercial MESH Wi-Fi type networks and not one of them will design
their network to go past two hops without jumping the traffic to another
frequency. You just can't scale things up that much, especially on a carrier
sense collision avoidance network. If you can convince the people you want
to see to set up their routes via specific digis to your area great. If you
are trying to see traffic in say Lubbock or Phoenix there just is no way
possible either of those areas can go three or more hops with a dumb routing
system (not saying the idea is dumb here, just no routing smarts) and not
affect either the West Coast networks or clobber all of Texas and/or OK and
Louisiana. These digi's really do talk that far when it is digi to dig
traffic. Don't believe me? Switch your local digis to the new system and
examine the paths from other digis you see on the map. It made a believer
out of me.



Thank You,
Brian Webster N2KGC
www.wirelessmapping.com <http://www.wirelessmapping.com>



-----Original Message-----
From: Earl Needham [mailto:needhame1 at plateautel.net]
Sent: Monday, July 04, 2005 5:05 PM
To: TAPR APRS Mailing List
Subject: RE: [aprssig] More digis are changing to the new paradigm


At 02:55 PM 7/4/2005, Eric Christensen wrote:
>You can't expect to see people on your screen nation-wide.  There
>isn't enough bandwidth available on a 1200 baud to do that.  Just
>because you want to see people that are 4 hops away doesn't mean they
>should change their paths as they would probably be adding to a
>sensitive network that is near them.
>
>Eric

         Suggest you stand back and look at the big picture of what I've
been trying to say for several years now.  The world is different
everywhere you go -- you have 50 stations within about 66 miles, I have 50
stations within 96 miles. (See
http://66.78.35.146/cgi-bin/near.cgi?call=KF4OTN and
http://66.78.35.146/cgi-bin/near.cgi?call=Kd5xb-2 )

         Except I only see a fraction of them because you have to use a
longer path that WIDE2-2 to get that far.

         And Bob -- who legitimately has a problem with congestion -- has
50 stations within only 13 miles.  The whole "New N-n Paradigm" was to try
a fix a problem that BOB is having, not me, and probably not you.  I
seriously doubt this type of congestion occurs outside of big cities.

         If you read my message again, you may notice that I never said I
want to see stations nation-wide.

         It would be really interesting if a few people from the east coast
would come set up their stations in, say, Hereford, Texas, and see just how
congested the system ISN'T.  We don't need these fixes out here because the
system isn't congested out here.

         Try walking a mile in MY shoes...
         Earl


Earl Needham, KD5XB, Clovis, New Mexico DM84jk
http://kd5xb-2.no-ip.info



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