§  80.289   Requirements for radio direction finder.

   (a) The radio direction finding apparatus must:

   (1) Be capable of receiving signals A1A, A2B and R2B emission, on each
   frequency within the band 285–515 kHz assigned by the Radio Regulations
   for distress and direction finding and for maritime radio beacons, and
   be calibrated to take bearings on such signals from which the true
   bearing and direction may be determined; and

   (2) Possess a sensitivity, sufficient to permit the taking of bearings
   on a signal having a field strength of 50 microvolts per meter.

   (b) The calibration of the direction finder must be verified by check
   bearings or by a further calibration whenever any changes are made in
   the physical or electrical characteristics or the position of any
   antennas, and whenever any changes are made in the position of any deck
   structures which might affect the accuracy of the direction finder. In
   addition, the calibration must be verified by check bearings at yearly
   intervals. A record of the calibrations, and of the check bearings made
   of their accuracy and the accuracy of the check bearings must be kept
   on board the ship for a period of not less than 1 year.

   [ 51 FR 31213 , Sept. 2, 1986, as amended at  63 FR 29660 , June 1, 1998.
   Redesignated at  68 FR 46973 , Aug. 7, 2003]