Many thanks!
I was not aware of any FCC rules about that.
We're out in the sticks in the middle of nothing. Not much around but cattle and rattlesnakes.
I was in fact trying to change the crystal in the tx. I purchased 2 new rx's and one came with both crystals (tx and rx) I thought I could just change tx crystal to fly another plane.
If a retuning is required to change channel on a tx, then this would explain the problems I've encountered. I was not aware of this either.
I'll just get new rx crystals so all rx's match my tx and I should be good to go!
Thanks.