Sec.  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]