47 CFR 80.268 - Technical requirements for radiotelephone installation.
All radiotelephone installations in radiotelegraph equipped vessels must meet the following conditions.
(a) The radiotelephone transmitter must be capable of transmission of A3E or H3E emission on 2182 kHz and must be capable of transmitting clearly perceptible signals from ship to ship during daytime, under normal conditions over a range of 150 nautical miles when used with an antenna system in accordance with paragraph (c) of this section. The transmitter must:
(1) Have a duty cycle which allows for transmission of the radiotelephone alarm signal described in § 80.221.
(2) Provide 25 watts carrier power for A3E emission or 60 watts peak power on H3E emission into an artificial antenna consisting of 10 ohms resistance and 200 picofarads capacitance or 50 ohms nominal impedance to demonstrate compliance with the 150 nautical mile range requirement.
(3) Have a visual indication whenever the transmitter is supplying power to the antenna.
(4) Have a two-tone alarm signal generator that meets § 80.221.
(1) The radiotelephone receiver must receive A3E and H3E emissions when connected to the antenna system specified in paragraph (c) this section and must be preset to 2182 kHz. The receiver must additionally:
(i) Provide an audio output of 50 milliwatts to a loudspeaker when the RF input is 50 microvolts. The 50 microvolt input signal must be modulated 30 percent at 400 Hertz and provide at least a 6 dB signal-to-noise ratio when measured in the rated audio bandwidth.
(ii) Be equipped with one or more loudspeakers capable of being used to maintain a watch on 2182 kHz at the principal operating position or in the room from which the vessel is normally steered.
(c) The antenna system must be as nondirectional and efficient as is practicable for the transmission and reception of radio ground waves over seawater. The installation and construction of the required antenna must ensure, insofar as is practicable, proper operation in time of emergency. If the required antenna is suspended between masts or other supports subject to whipping, a safety link must be installed which under heavy stress will reduce breakage of the antenna, the halyards, or any other supporting elements.
(d) The radiotelephone installation must be provided with a device for permitting changeover from transmission to reception and vice versa without manual switching.
(e) An artificial antenna must be provided to permit weekly checks, without causing interference, of the automatic device for generating the radiotelephone alarm signal on frequencies other than the radiotelephone distress frequency.
(f) The radiotelephone installation must be located in the radiotelegraph operating room or in the room from which the ship is normally steered.
(g) Demonstration of the radiotelephone installation may be required by Commission representatives to show compliance with applicable regulations.
(h) The radiotelephone installation must be protected from excessive currents and voltages.
(i) The radiotelephone installation must be maintained in an efficient condition.