See Guide to Transmitter Range From Artsci --- URL:

http://www.artscipub.com/simpleton/simp.range.html

Also see VHF/UHF Line of Sight Calculator
http://www.vwlowen.demon.co.uk/java/horizon.htm

And Calculating the Distance to the Horizon URL:
http://www.wolfram.demon.co.uk/rp_horizon_distance.html

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73 From The Wilderness Keyboard
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wrote in message
...
I seem to recall reading about a 'standard', it went something
like this,,,, a two meter antenna at 100 feet can "see" or be useable
for 17 miles. I don't recall where I read this,,, but would really
appreciate any and all input on the question,,,,,,,,,,,, How far can a
base two meter radio antenna transmit and recieve so as to be
'useable' when the antenn is 100 feet tall above the earth, and the
surronding area is fairly level. (no hills or mountains). I am
talking about a 50 watt base and 50watt mobil. If there is a formula
somewhere, would appreciate the input.
The reason I ask, is on the way by some very tall tv antennas
1000 and 1200feet, I got to wondering,,, they don't work well with
""my formula"" (17miles=100feet) they (the tv channels #2,#4 #5) are
out of 'gas' at about 70 miles.....?????????? Hope you can 'blumb up
my brain'. thanks in advance. cl.73