Background

Without prior notice, quite suddenly and unexpectedly, test broadcasts on behalf of Radio Australia were heard from a new location early in the year 1975.

In an endeavour to gain improved coverage into Asia, a beautiful new transmitter base was constructed for Radio Australia on Cox Peninsula, across the bay from Darwin in the Northern Territory. Three transmitters at 250 kW were installed and five log periodic antennas.

December 1968
Test broadcasts from this new facility began and regular programming with all three transmitters in use began in March 1970. These three transmitters were given feed-line callsigns, VLK, VLL and VLM.

However, on Christmas Eve 1974, the worst cyclone in Australian history struck Darwin, destroying 80% of the city, though fortunately the death toll was quite low considering the circumstances. The large modern transmitter station near Darwin was seriously damaged by Cyclone Tracy and it was evident that it would be off the air for a long period of time.

A temporary new station was urgently needed and site investigations in Western Australia ultimately led to the quick installation for a new facility located near Carnarvon on the central coast. Preliminary test transmissions to assess the feasibility of the projected new station were conducted from another location, Gnangara just north of the state capital Perth.

The Gnangara facility was previously in use as an OTC station which had been erected for the purpose of shortwave communication with a satellite tracking station on the island of Mauritius. There were three transmitters at 7.5 kW and several rhombic antennas at Gnangara.

Thus it was that unexpected test transmissions were noted from Gnangara, using two of the low powered communication transmitters in parallel, feeding into directional rhombic antennas. The program tapes were prepared in the Melbourne studios of Radio Australia and consisted of the familiar melody, "Waltzing Matilda", long segments of recorded music, and test announcements in English.

February 25 1975
These test broadcasts commenced on that date and concluded two weeks later on March 10. The schedule shows that seven different channels were in use during these two weeks of test broadcasts, ranging from the 31 metre band up to the 16 metre band. They were beamed towards Indonesia, South Africa and England.

This short series of test transmissions from Gnangara was considered to be a success and they demonstrated that signal propagation into the desired target areas would be adequate from Western Australia. Government approval was therefore granted for the erection of a new though temporary shortwave station at Carnarvon, further north in Western Australia.