British Army Wireless Sets C12 (1955)

Pye Wireless Sets C12 was designed between 1948 and 1950 as a private venture by Pye Ltd to replace the Wireless Sets No. 19 but was not initially adopted by the British Army because of plans to implement the Larkspur series of hermetically sealed equipments.

However, in 1955 it was adopted by the British Army as a temporary substitute for Station Radio C13 (the official Larkspur replacement for WS19) in armoured fighting vehicles, when the C13 development program ran late. The equipment then remained in service until the middle/late 1960s.

The equipment is constructed along similar lines to WS62 and has the same overall external dimensions as WS19.  It consists of a main transceiver unit, a separate power supply unit and an external aerial tuning unit.  The equipment can be connected to either WS19 or Larkspur control harnesses.

The frequency range covered is 1.6 to 10.0 MHz, and the equipment provides two channel "flick" tuning operation by means of switched main tuning capacitors, each with its own colour coded dial mechanism.  The ATU has twin tuning inductors switched by relays under control of the radio unit. Transmit power out is 3 - 5 Watts AM at 95% modulation and 4 - 8 Watts output on CW. The equipment is intended to work into vertical rod aerials of length between 8 and 32 feet, but will also operate into a 100 foot wire.

Different external power supply units were provided for 12 Volt systems or 24 Volt systems.  Each used a vibrator to provide 250 Volt HT supplies to the receiver, and a rotary transformer to generate the 400 Volt supply for the transmitter.   Transistorised versions of the PSUs were introduced in the early 1960s.

A modified version of Crystal Calibrator No. 10 (from Wireless Set No. 62) was used as a frequency reference.