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[aprssig] LINKn-N linear DIGI systems

Robert Bruninga bruninga at usna.edu
Thu Jul 29 21:47:08 UTC 2004


LINKn-N DIGIS:
By the way, when I recommended long linear strings
of LINKn-N digis, I am not saying that this is a necessity
everywhere there is an interstate.  But they do make
excellent sense in most of the cases I mentioned:

COAST from Deleware to Florida and I-95 from
Richmond down to Florida, where, because of the
lack of population density, a traveler might want to
use a path of 4 or 5 HOPS  along his travels, but
if he used WIDE5-5, his packets would not only go
along the course, but also 5 hops SIDEWAYS and
would QRM many dense APRS cities and square miles.

But by having a linear LINKn-N system, he only
hits exactly the 4 or 5 digis he wants and no others.

So, like everything else, use it where it applies, but
don't try to apply it where it is not  useful...  Bob

>>> bruninga at usna.edu 7/29/04 10:20:17 AM >>>
I have suggested some digipeater LINKn-N systems 
in the mid Atlantic area along the coast and some
interstates called:

 COASTn-N,  81LNKn-N,  85LNKn-N,  95LNKn-N

View the APRSdos screen capture of these digis with their
PHG circles overwhich I have drawn the suggeted LINKS:

 http://www.ew.usna.edu/~bruninga/aprs/LINKn-N.gif 

Notice how the COASTn-N system will be relatively
immune to QRM because of its distance from BALTO
and DC areas and how the I-81 system would use
digis on the WEST side of the I-81 valley which also
do not hear into BALTO/DC/Richmond etc...

I-95 will also be a GREAT long distance LINKn-N
system because it carries a tremendous load of long
haul traffic along the east coast to Florida.  And
advantageously,  from Richmond to Florida it does 
not go through ANY large cities or population densities.

Setting up these LINKn-N's is trivial since all the 
digi's exist already.  All the remote sysops need
to do is to change from:

 UIFLOOD WIDE,28,NOID
 UITRACE TRACE,28

To the new settings of:

 UIFLOOD LINK,28,NOID
 UITRACE WIDE,28

Where of course "LINK" is given the proper name for 
the link system involved.  

Existing users of WIDEn-N will not be affected though
those that use LONG hops will have LONGER packets
and should be encouraged to cut back to the hop
length recommended in their area (no more than 3
in the metro areas)...

For more reading on this new n-N Paradigm, you can read:

http://www.ew.usna.edu/~bruninga/aprs/fix14439.html 

ALSO, the screen capture above shows the now standard
PHG circles "for mobiles".  So although some gaps may 
appear along the links, these are only small gaps in
Mobile coverage, but they are not gaps in the LINK.  This
is because PHG circles are now routinely drawn at HALF 
their RF range to give a better user view of MOBILE
coverage.  Whereas the DIGI's can all talk to each other
easily beyond that.

The above screen capture is only a recommendation.  
Locals in the area who better know the coverage of
their digis should decide what is best.  But please think
in terms of routing LINKn-N paths "around" population
densities and not THROUGH them.

de WB4APR, Bob





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