[aprssig] DIGIpeater - Network performance

Robert Bruninga bruninga at usna.edu
Fri Jan 26 13:38:18 EST 2007


> How can you have over 60 to 100 stations in your Aloha circle?
> 240 is 2.4 to 4 times too many stations, right?

Yes!  The channel is still quite busy, but it is much much
quieter than it used to be.  Looking at the heard statistics on
most of these stations, it is easy for me to see that most of
them only come in a few times a day with a lucky hit, rather
than QRM all the time.  SO it is not as bad as it appears.

I'll run the station another 24 hours and be able to give
statistics on how many of those 240 statinos actually only
appear less than 10 packets a day... Thanks

Bob,Wb4APR

 
> http://www.ew.usna.edu/~bruninga/aprs/fix14439.html
> The 1200 baud 144.39 channel can only support an average 
> user load of about 60 to 100 or so APRS stations or objects 
> in an RF domain based on the typical transmission rates and 
> number of digipeaters and number of hops. ... This is 
> because any greater load than 100% channel capacity 
> guarantees lost packets due to collisions. The size 
> of your area that holds the number of users capable of 
> generating 100% channel capacity we call your ALOHA circle

> On Fri, January 26, 2007 1:02 pm, Robert Bruninga wrote:
> > But since 2 hop users are one tier less than 2 hop digi's,
most
> > of the 240 users I hear on RF these days are within my ALOHA
> > circle as we hoped:
> >
> > http://www.ew.usna.edu/~bruninga/aprs/DC-users.GIF





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