How MBS got its first radio transmitter

Percy Grainger’s music reminds broadcaster and composer Andrew Ford that Grainger was Australian. The way he puts music together, Ford reckons, is like what Australian men do in their sheds.

This transmitter shown in the image could be considered a superior product of what men do in their sheds. The French call it ‘bricolage’ – tinkering (but this was very high tech tinkering). If the men who built MBS’s first transmitter had sheds, they must have been radio shacks. They had built their own radio equipment, anything from a crystal set to an FM receiver; they had delved enthusiastically into radio in theory and practice, but none was exactly a radio professional. As amateurs they went where the professionals in Australia hadn’t gone. In the face of skepticism from the industry they challenged themselves to make an FM transmitter better than what was available commercially (only from overseas) and they did it using Australian materials and their own skills. Grahame Wilson, one of the men who built the first transmitter, explains: “We designed everything from square one, there were no circuits, no commercial designs, no prototypes, we did it all and ended up with some pretty fancy technology”.

Some of the work was done at home, but most of it – largely secretly, certainly unofficially – in the laboratories and workshop of the Physics Department at the University of Sydney, using some of facilities there. The Professor of Physics, Harry Messel, turned a blind eye to what was going on, in the early hours of the morning, when it was quiet. “It was better”, Wilson laughed “than working at home”.

Let us now praise famous men. Who were they? Putting money of their own into the project, and intending to buy things, they decided to become a company, ‘Music Broadcasting Constructors’: Grahame Wilson, Max Benyon, and Trevor Jarvie. Grahame Wilson admits to being obsessed with radio technology since early high school. His awareness of FM fired up when the ABC’s experimental FM broadcasts were closed down in 1961. At a Hi-Fi show some years later he saw an application form for the Music Broadcasting Society (one of its founder Trevor Jarvie’s recruiting leaflets). Wilson put himself down for the technical side. Another foundation society member, Michael Law contacted him, and Law’s radio technical background helped him identify a potential major contributor. Between them Law, Jarvie (himself technically literate) and Wilson came up with a blueprint for a radio station. Wilson recalls supplying ideas and some experience. Max Benyon soon joined them and “came up with the details”. Benyon, a graduate in electrical engineering from the University of Sydney, worked all his career for the Electricity Commission and its successors. He had enjoyed FM while working in the UK in the mid-1950s. He had built his own FM tuners, and like Wilson was disgusted in 1961 when the experimental transmissions were ended. Max Benyon became aware of MBS in 1971, like Wilson through one of the leaflets handed out by Jarvie on the steps of the Sydney Opera House, and passed on to him by a friend.

Graeme Tait’s involvement explains why the Physics lab became the transmitter construction shed. He was introduced to the others by Charles Barton, another MBS founder associated with Trevor Jarvie. Tait was doing a Ph.D. in Physics, and was the passport to using the labs after hours. Tait, says Benyon “was extremely good mathematically and practically, a combination by no means common”.

Max Benyon remembers: “We’d heard on the grapevine that the people in Melbourne were building their own transmitter. If they could, so could we”. MBS was in parallel development both in Sydney and in Melbourne. Melbourne’s Brian Cabena, who started the ball rolling towards fine music stations, had already made an AM transmitter and was known to have the technical expertise to design and build one for FM. The MBS technical crew in Sydney took some expert advice, but in the main did their own research and development. Grahame Wilson had a textbook which was very helpful.

This is a tale not of one transmitter, but of several. And it was a race against time, not so much to beat Melbourne as to meet the deadline for going to air. The decision of MBS in New South Wales to build its own transmitters was taken in March 1974. First the ‘constructors’ made two low-powered exciters – ‘exciter’ being the name radio engineers give to the combination of oscillator, modulator and sometimes audio processor, which together, to use non-technical terms, ‘make’ the FM signal.

The pair of exciters was used at two Hi-Fi shows to dispel groundless fears that transmissions on adjacent frequencies would interfere with each other. Benyon said: “We deliberately played classical music on one, and light music on the other. It was perfectly easy to tune in, although they were so close on the band”. This was just one prong of a campaign plan by MBS to demonstrate FM’s potential and viability to any in the radio world who would take notice – the trade, the regulating bureaucrats, radio enthusiasts, and listeners.

But the demonstration models were capable only of very localised transmission, within a room, or just a bit further. To make enough output for a radio broadcasting station, an amplifier was needed, a high-powered one. When an amplifier is added to the exciter broadcast engineers call the two together ‘the transmitter’. The amplifier needed to be successfully incorporated in what was being constructed, and along came a ham radio operator called Ray Shuetrim, who “built the amplifier into a box” – actually a cavity of quite complex design. In the picture, the dark part near the bottom is the front of the exciter; above that, behind the panel, is the amplifier.

By the time one of the exciters, already augmented, was being enhanced to still higher power, MBS had been offered, on 20 August 1974, a licence to broadcast. So had MBS Victoria. The urgency was heightened when a newspaper story headed ‘FM Radio Expected by End of Year’ mentioned that 2MBS would go to air by mid-December. Starting with only $300 in hand, the 2MBS technical team speeded up construction, and more cash was hastily gathered and donated to accelerate the completion. The deadline was met. Trial broadcasting began, fed by one of the original low power exciters, at 12 noon, 15 December 1974, using a simple antenna on the roof of loaned premises at 5 Alexander Street, Crows Nest. The search for suitable transmission sites, where antennas could be and how to obtain them, is a subject for another post. For the moment, let’s continue the history of the transmitter now to be seen in the museum.

The documentation with the exhibit rightly records that the first transmission was in mono. On the 20 December the transmitter was moved to the PMG’s nearby West St. tower. On 9 January power was raised to 400 watts, and on the 16 January the longed for moment occurred – the first licensed FM transmission IN STEREO. Almost immediately, at 1am, the phone rang at the 2MBS Alexander Street studio. It was a listener excited that the stereo indicator on the receiver had lit up for the first time.

Designed, built, improved, and maintained by 2MBS’s team of technical volunteers, the first transmitter gave yeoman service. In March 1977 it was moved to the new transmitting site on the AMP tower in the city centre, and it was then that the change was made to the frequency where transmissions have been ever since – 102.5 MHz.

Eventually the same team, plus additional volunteers, built a higher powered transmitter. The first transmitter was replaced in 1978 and retired to the reserve bench, for cases of emergency. Placed on standby, it had to be brought back into action more than once. Max Benyon, still forty years later the station’s adviser on transmission matters, and chair of its Technical Committee, agreed with Grahame Wilson that 2MBS’s first transmitter should be in the Powerhouse Museum. It was offered to that museum – an offer considered, but eventually turned down. Benyon, determined this transmitter should be preserved, took all the parts to Ian O’Toole’s museum at Kurrajong, where he reassembled it and turned it back on. It still works, taking Fine Music’s signal and re-transmitting it, in a local narrowcast, on the same frequency, 102.5.

David Garrett

David Garrett has been associated with Fine Music 102.5 since before it hit the airwaves 40 years ago. A regular on-air presenter, he is also a former Board member and Treasurer of the organisation. David is well known as a writer and speaker on music and history. His Ph.D. from the University of Wollongong explored how the Australian Broadcasting Commission became a presenter of concerts and builder of orchestras. David has taught history at Monash and Sydney Universities. For thirty years he was a music administrator and programmer, for Sydney Philharmonia, then for the ABC and Australia’s six symphony orchestras.

The research and writing for Fine Music: Forty Years of FM Broadcasting are made possible through a generous donation from station volunteer and former Chairman Ron Walledge.

For information on how to donate or subscribe to Fine Music 102.5 click here


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