I believe it only changes the output power on the transmitter ( Tx )
Europe strictly enforces their output level to no more than 300 meters ( CE )
Where USA, Northern Americas, allow 500 meter range ( FCC ), I believe it boosts the power a bit from
( ?w to ?w ) example ( not fact ) like 1watt to 2watt? But not sure exact wattage! Just an example!
( this all has to due with interference levels, and different country regulations )
( keep in mind, if you change your setting, make sure you can legally change it )
Hope this helps
I have a P2V, not sure on earlier models?
Jerry D
USA
( J Dot )