February 5, 2005 When German company Protona announced its Minifon P51 portable dictation machine in 1951, it caught the world's imagination and was seen as a solution for myriad problems. The Minifon directly catalysed the invention of the "Black box" flight recorder, was used in countless commercial processes around the world and was a natural for the Cold War espionage activities of every intelligence agency in the world.
When the upgraded P55 was realeased in 1955, it was available with a microphone designed to look like an expensive wristwatch, and was clearly designed for the clandestine recording of conversations and its use can be traced in many of the espionage trials of the late fifties and sixties including the famous Petrov Affair and the trial of Jack Ruby (who shot Lee Harvey Oswald who supposedly shot American President J F Kennedy).
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This week Gizmag came across a complete, mint condition P55 with watch accessory - a fascinating example of just how far leading edge technology has progressed in the last half century.
The watch doesn't function as a watch, but instead is a miniature crystal microphone. It is worn on the left wrist, with the wire (no Bluetooth in those days) running up the wearer's arm to the Minifon recorder which was held in place under the wearer's arm and covered by the suit jacket.
The current owner of the Minifon kit, John Kenny, inherited the device 35 years ago.
"The device belonged to my uncle from new and when he passed away, it was passed on to me. My Uncle was a publican, a speech-writer for a (Australian) Prime Minister and head of the Australian Hotels Association but never a spy - at least as far as we know. His hobby was film and sound and one of his hotels - the Queens Arms in St Kilda, was one of the first in Australia to be wired for stereo sound and had a mini picture theatre upstairs for family use only."
Unlike the cassette and miniature tape recorders so common in the last 30 years, the first portable voice recorder did not record on tape - it recorded on very fine 0.005 mm diameter nickel-chrome wire.
The Minifon's internals are hence a masterpiece of miniaturization and mechanical engineering. To achieve a recording time of four hours the wire is actually 2.9 kilometres long and contained on a reel 4.5mm in diameter, with the head moving up and down to smoothly spool it on each reel.
The kit sold in 1955 for the equivqalent of US$350, an indication of the exceptional quality and workmanship evident from viewing the device.View gallery - 5 images