C42    C45

 The C42 and the C45 are 1950s vintage VHF transmitter receiver sets. The C45 covers low band VHF and the C42 covers high band VHF. These radios were generally used in vehicular applications such as in tanks and LandRovers. Not being synthesised, they tend to drift  and have a somewhat broad transmission. They are beautifully constructed internally.

Below:    Antenna Tuning Unit.

Below: DC distribution panel.

COMMENTARY

Built as a replacement for the Wireless Set No.19, the C45 and C42 were a good step forward. Whilst not synthesized, there are a good, solid set that saw widespread use throughout the Commonwealth.

The station consists of the transmitter/receiver unit, vibrator power supply and antenna tuning unit. The antenna tuning unit is mounted to the body of the vehicle and serves as a base for a whip antenna. Audio junction boxes route audio around the vehicle allowing intercom usage. There was also a power distribution panel for 12 or 24volt distribution.

The set has a crystal calibrator for determining correct operating frequency. The receiver has a squelch circuit.
The system was to designed only to operate with an 8 foot whip antenna or an elevated aerial on a 27ft telescopic mast.

The receiver is a dual conversion superheterodyne. There are three RF tuned circuits.

The set is hermetically sealed. An internal fan circulates air around the case. The unit is beautifully built. For servicing it opens up like a book.

I know of several people that have successfully used this equipment on the ham bands. Power output is good, although tuning of the transmitter is quite esoteric. The major difficulty with using the set is drift. 

TECHNICAL SPECIFICATIONS

Frequency Range
    C42    36-60MHz
    C45    23-38MHz
Mode    FM
Power Output    1/4Watt or 15Watts
Supply Voltage    12V or 24VDC with appropriate vibrator unit
 

CONSTRUCTION

Below: Vibrator unit.

Below: C42 top view.

Below: C42 top view with chassis opened out. Everything is easily accessible. At top left of shot is the dial film.

OVERALL RATINGS

    Engineering rating (taking into time of design).

             This radio was a huge leap forward from the World War 2 radios it replaced. The layout is a work
             of art. 9.5/10

    Fitness for purpose rating

             Its popularity throughout the Commonwealth speaks for itself. 10/10

    Usefulness as ham equipment rating

             Quite functional although does drift and has a broadish emission. 8/10.

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