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[aprssig] APRS experiment along I-40, mapping vs. voice alert vs. local info

Robert Bruninga bruninga at usna.edu
Fri Jul 16 17:30:31 UTC 2010


> >> To me, this is the exact problem with Voice Alert.
> >> Who wants to drive down the interstate and have
> >> a 20 second QSO, just to prove that you can?
> 
> Who says that the only contact you will make are 
> those with hams traveling the opposite direction? 
> You could make contact with someone traveling the
> same direction, and have a *very* long QSO that 
> otherwise would not have happened.

I had to think abouit this a while to figure out why it rarely
works that way, and then of course it hit me...  The
probabilities of "running" into someone traveling the same
direction is practically zero (except GOING to Dayton or coming
home)...

At 50 cars per minute from the other direction, you pass maybe
3000 cars per hour in the opposite lane.  But on your side of
the road, you can drive for hours and still be within simplex
range of the same 50 cars that barely changes...  Over an 8 hour
trip, that's 24,000 cars (about 48 hams) you might pass on the
other side, but on your side of the road, you are stuck with
that same motley 50 cars going your direction.  And out of 50
cars, there is only a 10% chance of there even being one ham.

And even smaller that he is carrying APRS,
And even smaller than that that he has a two-way APRS
And even smaller than that, that he understands and uses VA
effectively or has his volume up like it should be......

Just some thoughts...
Bob, WB4aPR







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