Maybe then possibly maybe not, you never identified which rX's you have. Most older Futaba Rx's were center tuned to either the upper or lower half of the band. This is unlike other brands or the newest Futaba Rx's which are center tunned accross the entire band.

So if you have one of the hi/lo tunned Futaba Rx's then channel 35 is the demacation and if it was ch 20 then it you cannot us a ch 41 crystal in it and receive full performance. To make this change you would need the send the Rx in for a retune. Agine this does not apply to other brands and was just a Futaba thing.

John