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
the Larkspur series of hermetically sealed equipments.
in 1955 it was adopted by the British Army as a temporary substitute
Station Radio C13 (the official Larkspur replacement for WS19) in
fighting vehicles, when the C13 development program ran late. The
then remained in service until the middle/late 1960s.
The equipment is
along similar lines to WS62 and has the same overall external
as WS19. It consists of a main transceiver unit, a separate power
unit and an external aerial tuning unit. The equipment can be
to either WS19 or Larkspur control harnesses.
The frequency range
is 1.6 to 10.0 MHz, and the equipment provides two channel "flick"
operation by means of switched main tuning capacitors, each with its
colour coded dial mechanism. The ATU has twin tuning inductors
by relays under control of the radio unit. Transmit power out is 3 - 5
AM at 95% modulation and 4 - 8 Watts output on CW. The equipment is
to work into vertical rod aerials of length between 8 and 32 feet, but
also operate into a 100 foot wire.
external power supply units were provided for 12 Volt systems or 24
systems. Each used a vibrator to provide 250 Volt HT supplies to
receiver, and a rotary transformer to generate the 400 Volt supply for
transmitter. Transistorised versions of the PSUs were introduced
the early 1960s.
version of Crystal Calibrator No. 10 (from Wireless Set No. 62) was
as a frequency reference.