§ 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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