RADIO BEACON

New Zealand Herald, Volume LXXII, Issue 22243, 18 October 1935, Page 12

RADIO BEACON

APPARATUS AT TIRI TIRI SATISFACTORY TESTS AID TO NAVIGATION A radio beacon, the second to be installed on the New Zealand coast, is now in operation at Tiri Tiri Island. The tests of the apparatus have been completed, and are considered to have been highly satisfnefcory. The Government steamer Matai, which sailed from Auckland early on Tuesday morning for the northern and west coast lighthouses, carried out the trials. The vessel first mado a series of observations while circling near the island, and the arc was gradually widened until finally the Matai reported an excellent reception of the beacon's signals when off Cape Brett, some 100 miles from Tiri Tiri.

The beacon, which has been erected for the Marine Department by tho engineers of tho Post and Telegraph Department, is entirely automatic in action. It is controlled by a special clock which switches on the power at tho hour, and switches it off again at a quarter past tho hour. The actual transmission of a special characteristic signal is performed by an ingenious device technically known as tho " autosender," which comprises a small electric motor driving a circular disc, the edges of which are perforated with slots corresponding to the beacon's code of dots and dashes. A spring flicks in and out of tho slots, as the disc rotates, thus breaking tho circuit and sending tho signals to the aerial. An ordinary morse key is provided to take the place of the " auto-sender for the purpose of transmitting messages or testing. In the event of a fault developing, thus interrupting the beacon's signals, an alarm system is set in motion which rings a boll commanding the attention of the lighthouse keeper on tho island. Tho beacon's aerial is suspended between the top of the lighthouse and a 65ft. tubular steel mast, which makes a prominent mark on tho skyline when approaching Tiri. Most modern overseas vessels are equipped with wireless direction finders which enables them accurately to ascertain the bearing from which a radio signal is received. Hence ships, either approaching down tho coast from the north or entering the Gulf by way of Cuvier Island, will tune in to the wavelength of the beacon, listen for its characteristic signal, and obtain a true bearing and thus be able to proceed to port regardless how thick tho weather might bo.