§ 80.911   VHF transmitter.

   (a) The transmitter must be capable of transmission of G3E emission on
   156.800 MHz, 156.300 MHz, and on the ship-to-shore working frequencies
   necessary to communicate with public coast stations serving the area in
   which the vessel is navigated.

   (b) The transmitter must be adjusted so that the transmission of speech
   normally produces peak modulation within the limits 75 percent and 100
   percent.

   (c) The transmitter must be certificated to transmit between 20 watts
   and 25 watts, on each of the frequencies 156.300 MHz, 156.800 MHz and
   on ship-to-shore public correspondence channels, into 50 ohms effective
   resistance when operated with a primary supply voltage of 13.6 volts
   DC.

   (d) When an individual demonstration of the capability of the
   transmitter is necessary the output power requirements prescribed in
   this paragraph must be met as follows:

   (1) Measurements of primary supply voltage and transmitter output power
   must be made with the equipment drawing energy only from ship's
   battery;

   (2) The primary supply voltage, measured at the power input terminals
   to the transmitter, and the output power of the transmitter, terminated
   in a matching artificial load, must be measured at the end of 10
   minutes of continuous operation of the transmitter at its full power
   output.

   (3) The primary supply voltage must not be less than 11.5 volts.

   (4) The transmitter output power must be not less than 15 watts.

   (5) For primary supply voltages, measured in accordance with the
   procedures of this paragraph, greater than 11.5 volts, but less than
   12.6 volts, the required transmitter output power shall be equal to or
   greater than the value calculated from the formula

   P=4.375(V) -35.313

   where V equals the measured primary voltage and P is the calculated
   output power in watts."

   [ 51 FR 31213 , Sept. 2, 1986, as amended at  54 FR 40059 , Sept. 29, 1989;
    63 FR 36607 , July 7, 1998]

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