47 CFR § 80.355 - Distress, urgency, safety, call and reply Morse code frequencies.
This section describes the distress, urgency, safety, call and reply carrier frequencies assignable to stations for Morse code radiotelegraphy.
(a)Frequencies in the 100-160 kHz band. The international calling frequency in the 100-160 kHz band is 143 kHz using A1A or J2A emission. When a ship station operating in the 100-160 kHz band desires to communicate with a coast station, it must call on the frequency 143 kHz unless the International List of Coast Stations provides otherwise. Coast stations must reply on their normal working frequency in this band. Only individual calls, replies to such calls, and transmission of signals preparatory to traffic may be transmitted on 143 kHz.
(b)Frequencies in the 2000-27500 kHz band -
(1)Ship station frequencies. The following table describes the calling frequencies in the 4000-27500 kHz band which are available for use by authorized ship stations equipped with crystal-controlled oscillators for A1A, J2A, J2B, or J2D radiotelegraphy. There are two series of frequencies for worldwide use and two series of frequencies for each geographic region. Ship stations with synthesized transmitters may operate on every full 100 Hz increment in the 0.5 kHz channel for the frequencies listed, except for 100 Hz above and below those designated for worldwide use. During normal business hours when not communicating on other frequencies, all U.S. coast radiotelegraph stations must monitor the worldwide frequencies and the initial calling frequencies for the region in which it is located. The specific frequencies which must be monitored by a coast station will vary with propagation conditions. The calling frequencies which are routinely monitored by specific coast stations can be determined by reference to the ITU publication entitled “List of Coast Stations.” Initial calls by ship stations must be made on the appropriate initial calling frequency first. Calls on the worldwide frequencies may be made only after calls on the appropriate initial calling frequency are unsuccessful.
Ship Morse Calling Frequencies (kHz)
(c)Frequencies in the VHF bands.
(1)Survival craft stations using 121.500 MHz may be assigned A3N emission for radiobeacon purposes.