47 CFR § 97.111 - Authorized transmissions.
(a) An amateur station may transmit the following types of two-way communications:
(1) Transmissions necessary to exchange messages with other stations in the amateur service, except those in any country whose administration has notified the ITU that it objects to such communications. The FCC will issue public notices of current arrangements for international communications.
(2) Transmissions necessary to meet essential communication needs and to facilitate relief actions.
(5) Transmissions necessary to exchange messages with a station in a service not regulated by the FCC, but authorized by the FCC to communicate with amateur stations. An amateur station may exchange messages with a participating United States military station during an Armed Forces Day Communications Test.
(b) In addition to one-way transmissions specifically authorized elsewhere in this part, an amateur station may transmit the following types of one-way communications:
(1) Brief transmissions necessary to make adjustments to the station;
(2) Brief transmissions necessary to establishing two-way communications with other stations;
(4) Transmissions necessary to providing emergency communications;
(5) Transmissions necessary to assisting persons learning, or improving proficiency in, the international Morse code; and
(6) Transmissions necessary to disseminate information bulletins.
(7) Transmissions of telemetry.