Wireless of the Week - week 38

[Bruce Parker (RIP)]

Infantry-tank communication is vital. Tank crews, cocooned in their armoured hulls, needed the ears and eyes of the infantry to protect them, and the lightly armed infantry needed the tank’s guns and mobility to keep them safe. Getting messages between the two parties, however, was problematic and not entirely solved by attaching a telephone set to the rear deck of the tank as was first tried. A better idea, and one that was probably done unofficially at first, was to carry an infantry man-pack radio inside the tank to communicate directly to the infantry using identical sets.

The idea was a success, and the first official version, called the Plan A installation, used a standard Wireless Set No.38 Mk.II and battery inside the tank, but adapted the aerial system to use an antenna outside the vehicle for obvious reasons and connected to the tank’s Wireless No.19 set by a special No. 12 Control Unit. A more permanent solution developed in 1944 was the Wireless Set No.38 AFV, called the Plan B installation. It was a purpose built 38 set designed for use inside tanks and having its own power supply unit that ran off the vehicle’s electrical system instead of replaceable dry cell batteries. Additionally, special control units that were needed to operate the tank’s 19 set were built that included switch settings to allow the crew to speak and receive on the 38 AFV set.

The Wireless Set No.38 AFV had two units. First is a sender receiver that was in an identical case as the regular No.38 Mk.II set, but with an aerial lead and 12 point connector designed to work with the tanks power and control systems. The second, again in a case similar to the regular 38 set, was a vibrator power supply unit that ran off the vehicle’s electrical system instead of replaceable batteries. The regular 19 set No.1 and No.2 Control units were replaced with No.16 and No.17 units that did the same job but with the extra ability to switch to, and talk on, the 38 AFV set. As a result, the OFF/RECEIVE/SEND switch found on the regular set was fared over on the AFV version.

An aerial lead ran from a socket on the set face to an aerial base on the tank turret roof, where a regular 19 set aerial made of ‘F’ sections was used. Both the 38 AFV and Power Supply Unit were mounted with a waterproof cover on top of or near the tank’s 19 set to be operated by the crew’s wireless operator.