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COLLINS VHF Transmitter
17 L-7A

USA 1967.

This is my Collins 17L-7A, a VHF transmitter, works fine. I bought it for less than 10$ - without tubes. I need over one year to get the  tube for the end stage, a 6884 beam power tetrode, manufactured by RCA, a really rare item.
The transmitter were build in 1963  in combination with a Receiver 51X-2B for use in airplanes and needs 27,5 Volts. The frequency tuning is arranged by a Remote Control Unit 614U. The control unit drives - with a 7-wire logic  - an autopositioner system inside the transmitter whitch selects and connects the proper crystals into the oscillator circuit.
Even with the help of the well documentation  an awful reverse engineering act to get this units working: to watch the motor driven frequency justify inside the transmitter by switching the 614U is at the other hand an enjoyable activity then.

DEPARTMENT OF THE ARMY: Radio sets AN/ARC-73 an AN/ARC-73A, Field and Depot Maintenance Manual TM 11-5821-217-45, Wachigton 25, D.C., 1962.
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