47 CFR § 80.89 - Unauthorized transmissions.
Stations must not:
(a) Engage in superfluous radiocommunication.
(b) Use telephony on 243 MHz.
(c) Use selective calling on 2182 kHz or 156.800 MHz.
(d) When using telephony, transmit signals or communications not addressed to a particular station or stations. This provision does not apply to the transmission of distress, alarm, urgency, or safety signals or messages, or to test transmissions.
(e) Transmit while on board vessels located on land unless authorized under a public coast station license. Vessels in the following situations are not considered to be on land for the purposes of this paragraph:
(1) Vessels which are aground due to a distress situation;
(2) Vessels in drydock undergoing repairs; and
(f) Transmit on frequencies or frequency bands not authorized on the current station license.