Bald Hills Radiator

The National Broadcasting Service Radio Transmission Centre is an approximately 43 hectares (110 acres) site at 99 Kluver Street on the corner of Bracken Ridge Road, Bald Hills, facing west into Kluver Street and bounded by Taragon Street in the south and Hoyland Street in the east.[1]

The VLQ STCA880A transmitter is a very early model high powered (10 kW) high frequency transmitter. It is built from very old technology, its design and construction pre-dating both the transistor and the silicon chip.[1]

Relying on extremely large glass and metal radio valves, the final amplifier valves requiring a water cooling system, the transmitter in operation presented a truly awesome appearance when in operation, supplemented by a sound effect as the cooling system pump and fan operated. In a paper presented to the Institution of Engineers, Australia shortly before his death, Sanderson wrote:[1]

"These early units with prolific meters and open mesh panels, behind which the large glass transmitting valves glowed cherry red, contrasting with the strange blue pulsating plasmas of the mercury vapour rectifiers, had a personality and character which is totally lacking in the sterile steel boxes, the state of the art highly complex, almost non repairable transmitters of the 90s."

Particular qualities of the STCA880A are its robustness and its reliability, evidenced by the decades of high quality service it gave before it was finally retired, mainly because the valves vital for its operation finally went out of production. It was in either full-time or reserve service for forty five years, from 1943 until 1988.[1]

The Bald Hills unit was the third of its type, preceded by one at Laverton and another at Ballarat, both for the RAAF. It was the first NBS short wave transmitter in Queensland and the second in Australia. Its NBS predecessor, code named VLR, was operated from Victoria. It was not of the same type.[1]

To cool the anodes of the power output valves, duplicate pumps powered by 3-4 hp 2,900 RPM three-phase electric motors were installed in an adjoining room. A fan cooled external reaiator was installed on a patio adjacent to the pump room. As the anodes operate at 12,000 volts, low conductivity cooling water was essential, and a still was installed to ensure a continual supply.[1]

The existing vertical radiator is a triangular section lattice steel structure, 204m high and with 8 ft (2.44m) sides, guyed at four levels in three directions. The earth system consists of 120 copper wire buried radials, each 200m long. The mast is energised by separate six wire lines, each 460m long.[1]

The building lies on the western (high) side of the site. It was first used to accommodate the 4QR transmitter, which was shifted overnight on 23–24 March 1942.

Other buildings include:

• the foreman mechanic's residence, 1944
• the emergency engine house, 1950
• the coupling hut, 1962
• the transmitters

Other transmitters at the site include:[1]

• Stand by (10 kW) 4SU-11A (1948
• Stand by (2 kW) 4SU-16C (1951; ex 4QN Clevedon, 1960)
• 4QG main (10 kW) 4SU-64 (1963)
• 4QR main (50 kW) 4SU-38 (1963)

The VLQ transmitter STCA880A (1943) constructed for the National Broadcasting Service was the first high frequency transmitter in Queensland and the second in Australia. It is the last of its type in the world and is a relic of a period when high frequency (short wave) transmissions were the most favoured means of broadcasting to country areas. It was used extensively on broadcasts to Papua New Guinea. It was at the vanguard of the era of shortwave transmission which started when it and the Bald Hills centre were both new.[1]

It illustrates an important phase of the very rapid development of the National Broadcasting Service's Queensland operations. This phase began at a relatively early stage in the history of the radio broadcasting in Australia. It enabled access for the first time to radio services for communities in inland and remote centres, thereby reducing their isolation.[1]

The transmitter is of totally Australian design and has a very high content of Australian manufacture, only meters and valves being imported. Its operation was water cooled, a technological practice of the time and was in either full-time or reserve service for forty five years, from 1943 until 1988. It is completely preserved, housed in its original 1943 location.[1]

The transmitter is a very significant historical relic, as it is probably the only surviving specimen of this very interesting short wave transmitter type. The design by STC dates from the late 1930s. It has been recommended that the equipment should be retained as a broadcasting heritage exhibit.[1]

The other transmitters on the site form, with STCA880A, Australia's largest collection under one roof of retired and operating radio transmitters. Dating from 1948 or possibly earlier, they are, except for one recovered from 4QN Clevedon in 1960, in their original locations.[1]

The significance of the site lies essentially in its connexion with the transmitters. The aerial, erected in 1947, has become a very well known local landmark.[1]

Their significance attaches to the transmitting equipment housed in the main building, a unit purpose built in 1941-42 and modified or extended on at least four occasions since.[1]

Two series of photographs were taken of the erection of the first aerial in 1941 and of its spectacular demolition in 1987. These, with annotations by the late Douglas Sanderson, were presented by the Institution of Engineers Australia, to the John Oxley Library in 1994.[1]

• Jordan, Geoffrey (2016). Bald Hills radio centre : a nostalgic look into a bygone era of radio broadcasting 1937-1988. [Morayfield, Qld.] Geoffrey Jordan. Retrieved 10 September 2018.

Media related to Bald Hills radiator at Wikimedia Commons

• "1941 - ABC Brisbane". The History of Shortwave Radio in Australia. Archived from the original on 10 September 2018. Retrieved 10 September 2018.