[Geysers] GMRS radios compatibility

[Mike O'Brien]

> Have any of you had experience with Midland GMRS radios?  I am
> interested in 5 watt GXT500 radios which claim a 14 mile range
> (line-of-sight).  My guess is that they might be able to reach from
> Upper to Lower Basin (around 7 miles of signal blocking terrain).  Am
> especially interested in knowing how batteries hold up when transmitting
> on 5 watts.

	I wish I could be more encouraging, but more power doesn't
increase transmit range as you wish it would.  Ten times
the power only gives you about three times the range, due to
the inverse square law (details on request).  Ham radio operators,
who are supposed to know about this stuff, still have trouble
with it.

	Also, the frequencies at which both GMRS and FRS radios
operate (400 MHz band) are fairly line-of-sight, so more power
doesn't buy you that much.

	I once was able to talk via hand-held radio from
Sentinel Meadows to the Inn, but I did so by using the ham
radio in my car as a cross-band repeater, blasting out at 50 watts
on 2 meters (144 MHz).  In fact that worked great, but would
be tricky and expensive for the average person.  The car radio,
running unattended, was both more powerful and had a much larger
antenna (so it could hear the guy at the Inn).  You need a ham
license to pull this off, but those have become significantly
easier to get these days.

	(Uh, right, cross-band repeater is hamspeak.  I had
a handheld radio running on 440 MHz.  It reached as far as the
car, in the Ojo Caliente parking lot.  The radio in the car
listened on a particular frequency on 440, and whatever it
heard there, it would blast out on 144 MHz at 50 watts.
Its antenna was large enough that it could hear my friend
at the Inn on his handheld, transmitting on 440 MHz.  With
help like that I had NO trouble talking to my friend in
his room at the Inn.)

Mike O'Brien