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During WW2 the Director General of Posts and Telegraphs made available Observation Centres across Australia for the monitoring of various frequency bands. These Observation Centre were fully manned by the Post Office with qualified Radio Operators who carried out radio surveillance work. These qualified radio operators formed what was known as the 1 Australian Discrimination Unit.

Observations Centres for the Radio Security Organisation were located in the following locations:-

Stuart Brown's father was a member of 1 Australian Discrimination Unit at the Sydney Observation Centre in a suburban house in Telegraph Road, Pymble, Sydney. He tracked a Japanese subversive who was using a Seventh Day Adventists radio station in Newcastle to transmit his messages. This subversive hid just under the sidebands of 2GB. 

Mr. Brown was permitted to have a communication receiver and his wife used to say he would switch it on whatever shift he had ended (24 hour rota in 12 days) and tune to just under 2GB and ask her if she could hear anything. They reckoned he had gone crazy, but eventually they were able to filter out the Morse Code signals using more refined receiving gear than his home built gear. All amateurs built their own radios in those days. The subversive used to go to an island somewhere off the coast near Coffs Harbour and then return to Newcastle to send his observed movements of ships which would then be attacked by the Japanese submarines much further north. 

He did not tell his wife the outcome of this above incident until some time after the war as he said it was still Classified. He had a mouth like a steel trap. When his son Stuart joined the PMG in the early sixties he became a telegraph technician, and worked on installations for Foreign Affairs and the military (stunt boxes for decoding transmission). It was only when Stuart had a security clearance that his father told him some of the things that they did during the war.

Neighbours in Pymble thought they were just young men sharing a house. The antennas were secreted in the eaves of the house and there was no outward appearance of what was set up inside the house. Their security was never breached. At the end of the war they were all promoted to corporals and had to do two nights a week training at Moore Park. They were only ever acknowledged after the war in a letter that "the boys at Pymble played an important part".



I'd like to that Stuart Brown for his assistance with this home page.


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 Peter Dunn 2015


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This page first produced 5 February 2005

This page last updated 25 January 2020