RADIO BEACONS.

Auckland Star, Volume LXV, Issue 148, 25 June 1934, Page 9

RADIO BEACONS.

FOR T ASM AN "HOP."

AIDS TO NAVIGATION.

MARCONI EXPERT'S VIEWS.

The necessity for the installation of radio beacons for the navigation of the air as well as the sea was stressed this morning by Mr. H. M. Dowsett, research manager for the Marconi Telegraph Co., who is a through passenger by the Aorangi for Vancouver on his return to London.

"I am looking forward to the not far distant future when Mr. Ulm will bo conducting an air service between Australia and New Zealand," lie said. "I hope by then that there will be a radio beacon at both ends of the route. These beacons give to the airman a particular signal indicating the direct course, the signal changing when the is oil that course. This system is being extensively used in the United States. When Sir Charles Kingsford Smith and Mr. Ulm were associated in their flight across the Pacific some years ago they were able to make use of the signals on, leaving San Francisco for a distance of about 300 miles. Afterwards they had to use ordinary navigation methods until they came in touch with the United States beacons -installed in the Hawaiian Islands.

Auckland to Sydney.. "At that time the apparatus for reception on the 'planes was not nearly so well developed as now," continued Mr. Dowsett, "and it should be possible with the latest instruments for an airman to keep in touch with the course beacons all the way from Auckland to Sydney. I am not in any way depreciating what was done during the Pacific flight, but merely endeavouring to show the improvements that are so rapidly taking place with the installation of more sensitive receivers. It is well known by the experts what design of beacon would be required for the 'hop' from Australia to New Zealand. "Such beacons could also be used as aids to navigation of the sea if they were required for that purpose. For instance, a ship could make use of the beacons in foggy weather. They would be different, of course, from the shortrange wave installations required on the coasts. The coast beacon, with a range of. say, 60 miles, would not be of much aid to a pilot flying the Tasmau. It would mean that he would have to practically fly 'blind,' as far as radio is concerned, except for receiving his bearings when practically on the coast. The coast marine beacons would not give direction with sufficient accuracy for such flights. The course beacons for aerial navigation are much more elaborate and powerful than those used for coastal navigation." As an alternative to the erection of powerful course beacons for the guidance of airmen, Mr. Dowsett suggested the installation of direction-finding land stations. Two beacons 100 miles apart could be established, from which the pilot would be given his distance within a range of 200 or 300 miles. It was necessary to have two stations. A 'plane would pick up the signals from both and calculate tho angle by cross bearings. That method was being used at Croydon in conjunction with associated stations at Fulham in Norfolk and Lympne, in Kent, and accurate positions were, worked out for 'planes crossing the English Channel. "I think every effort should be made to investigate the position with a view to the establishment of such stations in Australia and New Zealand at the earliest possible moment," said Mr. Dowsett. Types of Beacon. Explaining various types of radio beacon stations, Mr. Dowsett said the first was the station sending' out a known eignal in all directions. A ehip with a direction-finder picked up the signal, and from it took its direction. Tho second typo was one sending out a rotating beam. On receipt of this a ship was able to obtain its direction by a simple calculation with a stopwatch. For ordinary navigation piirposes 100 miles was considered an effective distance limit. Anything beyond that was of no practical use to shipping. Such stations did not require anything like tho power necessary for beacons directing the course of aeroplanes over long distance euch as across the Tasman. "You can have beacons of much shorter range than the ones I have enumerated for the guidance of pilots landing at aerodromes," explained Mr. Dowsett. ' "These would give the 'planes direction, the stations having a range of 20 or 30 miles. Of course the aircraft would have to bo fitted with corresponding apparatus. This could even give the pilot the proper gliding angle for landing. While these landing beame are still considered to be in' their experimental stag© there is no doubt that within the next year or so blind landing by their aid will become a practical proposition."