British Army Wireless
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 equipments.
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 1960s and
was manufactured for Pye Ltd by Garrett Engineering,
Leiston, Suffolk, UK.
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.
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.
version of Crystal Calibrator No. 10 (from Wireless Set No. 62) was used
as a frequency reference.