|This article was originally material for a broadcast of “Wavescan” via Adventist World Radio and now forms part of the Radio Heritage Collection ©. All rights reserved to Ragusa Media Group, PO Box 14339, Wellington, New Zealand. This material is licenced on a non-exclusive basis to South Pacific DX Resource hosted on radiodx.com for a period of five years from January 1st 2003. Author: Adrian Peterson|
Test Transmissions From A Temporary Site – Radio Australia Gnangara
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. This is what happened.
In an endeavor 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.
Test broadcasts from this new facility began in December 1968 and regular programming with all three transmitters in use began in March 1970. These three transmitters were given feed-line callsigns, VLK, VLL & 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 (CAR-NAR-von) 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.
These test broadcats commenced on February 25, 1975 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.
A few QSL cards were issued by Radio Australia for these test broadcasts though they must be quite rare these days. It was just 28 years ago next Tuesday that these test broadcasts from Gnangara on behalf of Radio Australia were suddenly and unexpectedly heard on the shortwave bands.
Radio Australia Gnangara
Year Date Event
1975 Feb 25 Test transmissions began Gnangara on behalf of Radio Australia
1975 Mar 10 Test transmissions concluded March 10, 1975Radio Australia Gnangara
Gnangara – Location
OTC station used as NASA satellite relay station
Erected when NASA operated satellite tracking station on Mauritius
Connected to Moree in NSW by landline
Gnangara – Facility
3 transmitters @ 7.5 kW for communication with Mauritius
Set of rhombic antennas
Gnangara – Radio Australia usage
Test transmissions on behalf of RA began Feb 25 1975
Test transmissions concluded March 10, 1975
RA usage, 2 transmitters in parallel
Programming, test transmissions, recorded announcements and music
Tapes produced in Melbourne studios of Radio Australia
Transmissions beamed to Indonesia, South Africa and England
On air 0100 – 2000 UTC
7 channels in 31 19 16 13 m bands
Tests as feasability study for installation of Carnarvon station
Carnarvon as replacement for damaged Darwin
AMP RA Thesis; 355 & 356
Interview retired RA engineer Reg Boyle 1979
Monitoring observations in Kandy & Colombo, Sri Lanka, 1975
RA Gnangara 21745 kHz 7.5 kW 26-2-75; AMP QSL card from RA
RA Gnangara 17895 kHz 7.5 kW 27-2-75; AMP QSL card from RA