As others have noted, with Futaba you need to stay within the same "band", i.e. channels 36-60, plus send your transmitter in for service ($30 or so).

My recommendation? If you can, find what others are flying, and pick a channel nobody else uses.

Also, be sure to ask around, there may be channels that "everyone knows" are problems. This happened in my club. I spent the money to change to one of these channels, only to find that the club never publicized the fact that the channel was banned, because "everybody knows, it's been so many years."