As @N1GAW said in another thread, you can get it for $5 at the track. If you find the Racing Radios trailer in the pit, they will usually flash your radio for you (at least they flash my BC75XLT). Make sure you bring a blank radio or have the file backed up at home. The alpha tags are great, and the channel numbers match up to the car numbers when possible. They'll give you all the freqs for all the classes, too.