§  80.875   VHF radiotelephone power supply.

   (a) There must be readily available for use under normal load
   conditions a power supply sufficient to simultaneously energize the VHF
   transmitter at its required antenna power, and the VHF receiver. Under
   this load condition the voltage of the source of energy at the power
   input terminals of the VHF radiotelephone installation must not deviate
   from its rated value by more than 10 percent on ships completed on or
   after March 1, 1957, nor by more than 15 percent on ships completed
   before that date.

   (b) When the power supply for the VHF radiotelephone installation
   consists of batteries, they must be installed in the upper part of the
   ship, secured against shifting with motion of the ship, capable of
   operating the installation for 6 hours, and accessible with not less
   than 26 cm (10 in.) head room.

   (c) Means must be provided for charging any rechargeable batteries used
   in the ship's VHF radiotelephone installation. There must be provided a
   device which, during charging of the batteries, will give a continuous
   indication of the charging current.

   (d) The VHF radiotelephone installation may be connected to the reserve
   power supply of a compulsorily fitted radiotelephone or radiotelegraph
   installation.

   [ 51 FR 31213 , Sept. 2, 1986, as amended at  58 FR 44953 , Aug. 25, 1993]