FCC wants us to all play nice and not swamp each other's signals...so air models get one set of frequencies (72 Mhz), and surface models--be it boat, car, truck, etc. get another set (75 Mhz).
There are exceptions, but this is what is generally accepted.
can i change it to 75 mhz. the reason i am asking this, i saw someone this weekend with a 7 channel air radio using it for a boat. Oh yea. it can also be changed to pcm.