[aprssig] low power APRS ? collision avoidance

K. Mark Caviezel kmcaviezel at yahoo.com
Sun Sep 26 13:45:38 EDT 2004


>From Pete: 
NO I AM NOT!!!!  In no way did I say anything to 
advocate that!!!!  I am
saying that collision avoidance is a necessary 
part of ANY shared
channel data network.  

>From Me:
We should realize the desirability of collision
avoidance as you are advocating (although I tend to
think it's a bit of a fantasy in areas like here in
Denver where we have some very high digi's.... there
is just no way that compromise antenna mobile units
will hear each other whereas the hilltop digis sees
and hears all), versus the practicality of some
simple, cheap, small, power-thrifty devices (such as
the Pocket Track).  Please realize that there are a
bunch of Pocket Trackers out there, and there will be
plenty more to come.  Instead of taking the tact that
'this is the way things should be', we could instead
come up with a low-impact way to welcome a ton of new
APRS users to APRS- they are coming!   Bob's 144.???
low power channel proposal may infact do just that. 
And I would infact argue that your statement that
"collision avoidance is a necessary part of ANY shared
channel data network" could be more accurately stated
as 'collision avoidance is a desirable part...' 
I have ran a completely deaf Pocket Tracker around
town here in Denver on 144.39 and have found that it
worked fine.   Anyone who is running 5 to 50 W I am
sure smooshed my packets just fine, meanwhile, I am
satisfied with number of packets that make it into the
network.   

All this is not to be contentious at all, I just want
to convey that the low cost/low power/small size
characteristics of something like the pocket track can
open up some applications that couldn't afford the
cost/size/weight/power of a more full fledged
solution. 

- KMC ng0x  


		
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