Yep. If you buy a TX and it has CH 54 in it when new and you want to change it to channel 57 you need to send it to the shop legally. Technically even if you take out one CH 57 TX crystal and then install a different CH 57 crystal it needs to go to the shop because no 2 crystals are identical. The FCC considers either action to be a modification to the tuning circuit.

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