Section 5(2) in The Merchant shipping (Radio Direction Finders) Rules, 1968.
(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.
