Theoretical range of a 5 watt transmitter and 1 microvolt receiver using
quarter-wave whip antennas on both ends of the link is about 3000 miles. 10
watt range is about 4300 miles.

Radio horizon (the point past at which VHF isn't going to be heard) at
20,000 MSL over perfectly flat ocean is about 280 miles. 5 watts and 10
watts will be heard roughly identical at horizon.

Jim




"Matt Whiting" wrote in message
...



Why would having twice as much power not be significant?

Matt