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Old May 1st, 2004, 01:21 AM
Mark W. Oots
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Default Wattage and distance of GMRS two-way radios


"Jeff Durham" wrote in message
...
(Hopefully, this does not get posted twice as last night, it didn't seem

to
go...)

Hi all,

In looking at a couple of different GMRS Radios, one of the main

differences
seems to be the wattage output and hence the claim of distance. For
instance, the Motorola T5950 outputs 1 watt where the Midland G-300

outputs
3 watts. That is definitely a difference in power and I am sure that

makes
a huge difference in battery life.

Here is my question -- on lake surrounded by woods where you do not have
line of sight to another person, how much distance can you really get
between the two units? If 1 watt gives you two miles through that

terrain,
would the three watt give you four miles? Anyone have any direct

experience
with the different wattage units? My neighbor and I hunt and fish on a

lake
that is about 6 miles long. I am curious if one unit or the other would
actually let you cover that difference. I doubt the one watt would do

that
because it only has a claim of 5 miles under optimal conditions where as

the
3 watt unit claims 10 miles.

Thanks,
Jeff



Speaking as one who sells radios (though not many GMRS) ...

Distance is more a function of antenna height than it is RF power. A half
watt will talk to the moon with no air, clouds, or other stuff in the way.
When a GMRS radio says 10 miles, it must mean hilltop to hilltop. FM radios
are strictly line of site. With a handheld that means to the horizon, or
about 5 to 6 miles, on flat ground (or water). Double the antenna height,
add 5 miles to the range. Power has more to do with penetration of
obstructions, though frequency also comes into play. GMRS freqs are
basically UHF as are FRS. GMRS radios require FCC licensing, FRS freqs do
not. For outdoor use, in rural areas, there are also VHF freqs called MURS
that require no license and work well. They fall under the Citizens Radio
Service, (same as CBs, but FM and roughly 150 MHz). They have the same power
limits as the GMRS freqs. For fishing and hunting applications, either works
fine most of the time. The FRS (Family Radio Service) was designed to give
you a way to call the kids in for dinner when they're out in the yard
playing, and so are not just limited in rage, but don't usually hold up as
well in heavy use situations. GMRS radios also share some freqs with FRS and
as a result, you can get a lot more interference than on the unique GMRS or
FRS freqs.

Decent brands might be, but not limited to Motorola (not the best bang for
your buck), Legacy/True Talk, Midland, Kenwood, and probably others I've
forgotten. Here we sell Motorola, Vertex Standard, Maxon/Legacy/True Talk,
Midland and Ritron, though not many consumer products.

You won't get 10 miles with any FM handheld, without a repeater. There are
GMRS repeaters scattered around the country, usually by subscription, and
you can set up a MURS repeater of your own with no license, but they are
rather pricey (not as much as a commercial 25 or 100 watt repeater, but
still over 1500 bucks).

Mark


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