47 CFR § 80.858 - Radiotelephone receiver.
(a) The receiver required by § 80.854(a) of this part must be capable of reception of H3E and J3E emissions on the radiotelephone distress frequency. The receiver must be capable of reception of J3E emissions on 2638 kHz and the receiving frequencies associated with the transmitting frequencies authorized pursuant to § 80.855(a).
(b) One or more loudspeakers capable of being used to maintain the distress frequency (2182 kHz) watch at the principal operating position and at any other place where the listening watch is performed must be provided.
(c) The receiver required by paragraph (a) of the section must:
(1) Have a sensitivity of 50 microvolts;
(2) Be capable of operation when energized by the main source of energy, and by the reserve source of energy if a reserve source is required by § 80.860(a);
(3) Be protected from excessive currents and voltages;
(4) Be provided with a nameplate showing the name of the receiver manufacturer and the type or model.
(d) The sensitivity of a receiver is the strength in microvolts of a signal, modulated 30 percent at 400 cycles per second, required at the receiver input to produce an audio output of 50 milliwatts to the loudspeaker with a signal-to-noise ratio of at least 6 decibels. Evidence of a manufacturer's rating or a demonstration of the sensitivity of a required receiver computed on this basis must be furnished upon request of a Commission representative.