Ever had a problem when swapping crystals?
I used to race r/c cars where we had up to ten cars on the track at a time. Even more during practice. I had 3 sets of crystals that I used just incase someone was on the same frequency as I was. This was sometimes the only way to get on the track because sometimes 3 other people also were on the same channel. To me, changing channels is a way of life. However, if you were to use the 72 mhz band (air) for cars or the 75 mhz band (surface) for planes, then that is a major problem.