Rack Mount FM Transmitter ? In Christmas Radio/Music/Videos/etc. Posted January 14, 2009 My experience with this unit as it is used at Texas Motor Speedway to transmit race day info both to radio and scanners and as stated in the manual. This units min wattage is 12w. The max is 20w so the 0 to max is misleading because 0 would be 12w where max would be 20w. You would be 11w over what FCC allows for Class 15 even at the min setting. You can not turn the power back like you think. You are limited within a set threshold.