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[aprssig] WIDEn-N question

Robert Bruninga bruninga at usna.edu
Wed Nov 4 13:41:42 UTC 2009


> I also encourage the Big DIGI's not to 
> respond to WIDE1, because they will pick 
> up the WIDE2.  Responding to both, the 
> Big DIGI transmits twice.

Actually I need to clarify that....  There are several issues
here:

1) If the big digi does not respond to W1-1, then the big digi's
are ignoring ALL mobiles in its footprint that are not covered
by a fill-in WIDE1-1.  And since the big digi's have probably 10
to 100 times the coverage of the small fill-in's, then this
approach essentially castrates the big digis...  The big digis
have to respond to both for this system to work.

2) Under New-N paradigm, the big digi's will never digi any
packet twice.  If they hear it first, they do the W1-1 and then
wont do the W2-1 later.  If the W1-1 hears it first, then the
big digi will only do the W2-1 once also.

3) Even if both the big digi and the fill-in hear it at the same
time. Both will TX at the same time (Dwait=0) and no one will
hear the W1-1 because the big digi will saturate the whole area.

That is the beauty of the W1-1,W2-1 two hop system.  It works.
And it only takes up ONE slot time at each outward tier, yet it
can use a Fill-in if that is all that hears it.
And there are no dupes causesd by it.  Evey digi will digipeat
it once and only once.  That is the intent.

> I also encourage Fill In DIGI to just respond to WIDE1-1.

Yes, that is essential.
 
> I recommend WIDE1-1,WIDE2-2 for mobiles in WPA.

Great!

Bob, WB4APR




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