Section 5 in The Merchant shipping (Radio Direction Finders) Rules, 1968.
5. Interference with Reception.
(1)At no time when a ship is at sea interference or mechanical noise produced by a radio direction-finder required by these rules or by other equipment in the ship shall be of such intensity as to prevent the efficient determination of radio bearings by means of the radio direction-finder.(2)Any ship which is provided with a radio direction-finder not being an existing installation shall also be provided with a communal aerial system for all broadcast receivers in respect of which it is impracticable to erect efficient and properly installed aerials which"(a)are outside a radius of 15.2 metres from the radio direction-finder aerial, or(b)do not rise above the base of the radio direction-finder; or(c)can be lowered quickly and stowed easily when the radio direction-finder is in use.
