I dont know anything about how the transmit power thing works, i have a 1/5 myself. What i do know is that west marine sells vhf handhelds that they say are waterproof 9 out of 10 times :roll: . i was a little upset after spending 200 bones on a "waterproof model"
. So i would recomend getting a standard horizon which west marine was very happy to exchange their pos for. great customer service not such a great product.
dave