Aural Radio Range - late 1930s


Early in 1936 Amalgamated Wireless (Australasia) Limited – commonly known to generations of Australians as AWA – installed, at their own initiative and cost, a medium frequency wireless beacon near Sydney/Mascot Aerodrome. This was the first pilot-interpreted radio navigation beacon in Australia (i.e. it not rely on a ground operator).

During the opening ceremony, the Minister for Defence, Sir Archdale Parkhill said that the Government had studied closely the aerial needs of Australia, and hoped to provide a complete radio service to aircraft. It was recognised that this would involve the Commonwealth in the expenditure of large sums of money. Remarkable advances had been made in other countries, but a thorough study would discount any suggestion that Australia was backward in wireless communications. The Minister declared that the Government had been criticised for inactivity, but it was the intention of the Government to do all in its power to assist civil aviation. He said the delay in constructing the beam was in fact fortunate, as it enabled Australia to benefit by the experiments overseas, with the result that the very latest equipment had been provided by the Marconi Company and erected by Amalgamated Wireless. No doubt many further beams would be erected, and Mr Fisk (Managing Director, AWA) was satisfied that any future stations would be constructed by Australian engineers with Australian materials. The beam would be available for operation on demand, and would be switched on at the scheduled times for air mail aircraft fitted with radio receivers.


The Aural Range was located on a large tract of vacant land at North Brighton, about 1½ miles south west of Mascot aerodrome, near the Kyeemagh polo ground. All evidence of its existence had vanished by 1939, soon after being superseded by the Lorenz Radio Range. A second beacon was destined for Melbourne/Essendon Airport, but this never eventuated.


The radio equipment was housed in a timber building, located near the centre of the aerial system. There were two aerial systems, each comprising two triangular loops and placed at right angles to each other, the base being 220 ft long and 65 ft high. Four timber masts were placed at the corners of a square, and a central mast supported the loop aerials.

The entire system was imported from England and assembled, and subsequently operated, by AWA technicians. The transmitter operated on a frequency of 295.3 KHz, and was modulated at 1 KHz (i.e. produced an audible tone for the pilot to hear on headphones). It produced 250 Watts of radio frequency power, and had a reliable range of reception up to 100 miles from Sydney. By means of a motor-driven cam, the audible tone was switched to feed one loop with a Morse Code “A” (represented by dot-dash) and the other loop with the letter “N” (dash-dot). When the pilot was in the zone of equal signal from both loops, he was on-course, and the equal strength of the A and N tones in his headphones was heard as a steady tone. While the courses were essentially at right angles (north-south and east-west), it was possible to slightly ‘bend’ the course. The system was not easy to use, having a high level of background atmospheric interference, making it difficult to discern the signal above the electrical noise.

The photo at the top shows the Aural Radio Range at Brighton le Sands. Below is the Notice To Airmen (NOTAM) that was published by the CAB to advise pilots of the beacon. The diagram clearly shows the 'A' and 'N' signal quadrants produced by the beacon, as well as the 'continuous tone' courses.

(Photo & NOTAM: CAHS collection)

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