C6770 Communications Receiver

C6770 Communications Receiver

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General Description

The AWA C6770 Communications Receiver was generally used in conjunction with the 3BZ Teleradio Transmitter and hence is commonly known as the 3BZ Receiver.

This equipment were derived from the 3B series which were used on outpost stations in the South West Pacific prior to WW2.

During the war the equipment was used by the Coastwatchers, who used the radios to report the location of the Japanese shipping, troops and aircraft movements from behind enemy lines.

There are many variations of the receivers, but they all have the designation C6770 as a suffix. Variations include different power supply requirements and various mounting arrangements.

Technical Data

The basic C6770 is battery operated (6/12v) , the 1C6770 is ac operated (105-130v/200-260v) and the 3C6770 is battery operated with a crystal locked position. The first two models cover 200kc-30mcs, with the latter covering 200kc-11.1mcs.

The receiver is a 5 valve superhet, designed to give economical and efficient operation where the larger type of communication receiver is not called for.
The valve line up is as follows: ID plate

6U7GRF Amplifier
6J8GMixer Oscillator
6J8GIF Amp and BFO
6G8GDetector, AVC,1st Audio
6V6GPower Output (AC Mains models)
25L6GPower Output (DC Mains models)
5Y3Rectifier (AC Mains models)

Tuning Ranges:200 - 515 kc; 545 - 1650kc; 1.5 - 4.6 mcs; 3.5 - 11.1mcs; 9 - 30mcs In the case of the 3C6770, the 9-30mcs range is replaced by a crystal locked position.

Technical Details: Power Output is 850mw, Output Impedance is 1.5 or 8 ohms for a permag speaker, plus 600 ohms for headphones or line.

IF frequency is 535kc, the BFO frequency is 178.3kc (uses 3rd harmonic injection)

Illustrations of the set

c6770 Top view

c6770 bottom view

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© Ian O'Toole, 2009. Page created: 14/04/04 Last updated: 4/12/2009