I just got a futaba 7cap that has an 18 transmitter crystal, I have a futaba r-114fm reciever, and I tried to put my old channel 52 crystals in to try them and nothing works on the plane. I think I need the low band crystal as stated in the manual, I will get correct channel 18 crystal tomorrow and see what happens.

I too am confused by this. Some here say any crystal between 11 and 60 will work, but the manual says 11 thru 35 and 36 thru 60 are differant and will not work. Sure seems that way to me. Any more input out there on this issue?