Don’t Believe The Hype

Lies, damn lies, and FRS/GMRS range advertisements…

It seems like every new FRS or GMRS radio that comes out these days also comes with new and more highly inflated range numbers.  The one that set me off today was a TV ad from Cabela’s touting handheld FRS/GMRS radios with a 28 mile range (in camo, of course, which is another abomination against all that is holy in radio aesthetics).

Simple physics dictates that it’s highly unlikely that you’ll ever get anywhere near 1 mile, much less 28.  FRS is limited to .5 watts, and while GMRS can go up to 50 watts, most handhelds are likely to put out no more than 2 watts, especially using regular AA alkaline batteries.  Further, you have to have line-of-sight for the radio signal to propagate from the transmitter to the receiver.  Perhaps if you or your friend were on top of a mountain, with line-of-sight between the two of you and you used the ‘power boost’ feature found on some GMRS handhelds (which may push you up to 5 watts) you might be able to communicate over 28 miles. 

In the real world I’ve found that you can’t realistically expect more than about half a mile if there are any obstructions at all around you.  Further, the maximum line-of-sight propagation for open ground is limited to about 7 miles due to the curvature of the Earth.  If you want more than that you get into having to use a repeater mounted on a high tower (GMRS can do this, but you won’t be able to buy the equipment at Wal-Mart in a bubble pack).

Note: Edited after publish for minor restructuring.

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