The Highest Powered Mediumwave Station in the Southern Hemisphere

On previous occasions here in Wavescan, we have presented Part 1 and Part 2 in a four part mini-series on the topic of The Highest Powered Mediumwave Station in the Southern Hemisphere, the story of 2CO in Corowa New South Wales.  Today, we present Part 3 in this same series, and that will take us to a country relay station in another Australian state, this time the state of South Australia.

It was on June 23, 1929 that the Australian Broadcasting Company (ABCo) was formed, and they took over a total of eight mediumwave stations in six Australian states that were already on the air.  During their three year tenure of office, the shortlived ABCo established four more mediumwave stations, two of which both qualified for the title of the Highest Powered Mediumwave Station in the Southern Hemisphere.  These two stations were the aforementioned 2CO in Corowa, and then the South Australian 5CK in Crystal Brook, both of which utilized Australian assembled STC transmitters rated with an output power of 7½ kW.

The new 5CK at Crystal Brook was established to give radio coverage to the industrial city of Port Pirie and its surrounding agricultural areas.  Port Pirie was declared South Australia’s first
provincial city (1953), and it is the state’s second largest port, after Port Adelaide itself.

The new ABCo regional relay station 5CK was installed at a country location on Gladstone Road, three miles from the small town of Crystal Brook.  The new mediumwave transmitter, rated at 7½ kW output on 635 kHz, was installed in a newly constructed transmitter building.

Two lattice style steel towers 185 feet tall were erected 265 feet apart, and suspended between these two towers was a center fed Alexanderson style antenna system.  At each end of the antenna system was a drop down lead to earth, with a special tuning coli in a tuning hut for each. 

The antenna system at 5CK was similar in design and style to the somewhat larger antenna system that was erected for station 2CO three months earlier.  Described as a Multiple Tuning System, only three of these systems were ever erected in Australia; the aforementioned 2CO in Corowa New South Wales, this regional mediumwave station 5CK near Crystal Brook in South Australia, and the “new” 6WF when it was transferred from the Westralian Farmers Building in downtown Perth and rebuilt at Wanneroo in Western Australia (1934), two years after 5CK  was inaugurated. 

It will be remembered that the radio station at Wanneroo in Western Australia was also home to the ABC shortwave transmitters VLW and VLX, as well as for Radio Australia programming beamed to South Africa, Asia, and Antarctica.

Programming for the new 5CK came by landline from 5CL in Adelaide, with occasional local
inserts from a small studio in nearby Port Pirie.  The official opening ceremony was conducted at the 5CL studios in Hindmarsh Square in Adelaide on March 15, 1932, and one of the main speakers was the Post Master General Mr. James E. Fenton, who spoke from Canberra by landline.

Reception reports for the new 5CK were received from listeners throughout Australia, far and wide.  Listeners in Sydney and country Lismore in New South Wales, and in country Victoria, proclaimed triumphantly that the new 5CK was the strongest signal from any radio station in Australia.

As time went by, an additional new mediumwave station 5AN joined the studio production team in Hindmarsh Square, and this new station then provided most of the landline programming to 5CK.  To this day, 5CK is still on the air under its original callsign, and it now radiates 10 kW on 639 kHz.

It is true, that back then in the early 1930s, both 2CO in Corowa and 5CK in Crystal Brook were the most powerful mediumwave broadcasting stations in Australia, and also in the Southern
Hemisphere.  However, they did not retain that honor for very long; station 2YA in Wellington in the
sister dominion New Zealand soon took over that honor.  And that’s our story next time, when we present another episode of the interesting historic topic, The Highest Powered Mediumwave Station in the Southern Hemisphere.
(AWR-Wavescan/NWS 489)