RE: NEED RADIO HELP..FUTABA SKYSPORT-T4YF
Yes you can change crystals on the RX legally but the crystal must be the same brand as the Rx, it must be either a single or dual conversion crystal to match whether its a single or dual conversion Rx and it must be a Rx crystal. The Rx must be of the same modulation type (FM, AM or PCM) as the Tx (your Tx is FM) and lastly the Rx must be of the same modulation shift (your Tx is negative shift) either Negative or positive shift.
John