Wireless of the Week - week 23

[Bruce Parker (RIP)]

Let’s go back to the dark days at the very start of the Second World War when the B.E.F was dashing about France standing off the Germans and Matilda tanks were clanking about North Africa looking for Italians and finding the Afrika Korps instead. In the bustle of every British tank, rear of every wireless truck and in battalion headquarters was inevitably a Wireless Set No.11.

The Wireless Set No.11 was state of the art for its time. Unlike previous sets in development before the war, the 11 set was of a modular design allowing it to be adapted to many applications from tanks to mules, and had power supply units that needed nothing more than vehicle batteries to operate them and provide the correct voltages the set required. Multiple aerial systems and the ability to operate remotely with RCU’s (Remote Control Units) added to the versatility.

Originally a British set introduced in 1938, the set shown here is a Canadian one made by Canadian Marconi Company in 1941. It differs from its British cousin by having a green wrinkle finish instead of black. As shown, the set has a sender receiver on the left, a low power supply unit to its right and a high power supply unit beside that; however the set could be operated with just the low power unit. The set and supply units fit into an aluminum frame that could be adjusted for either configuration. The frame, if in a vehicle, was mounted with rubber shock mounts similar to 19 set ones. When used on the ground, the set came with a clip on face cover, often stenciled with “WIRELESS SET No.11” which, when removed, had two fold our legs and the cover became a table to put the set on and keep it out of the mud. Like many lids and covers, this one too had a metal plate with working instructions attached on the inside.

Connection between the units was with cables that plugged into sockets on the face of the components. A replaceable ammeter on the sender/receiver was protected by a quick release clear plastic cover. Aerial connections from the set went through a Condenser No.5 on the top of the sender receiver to either an aerial base or a Coupler Unit C which allowed the aerial to be remote from the set. A remote Control Unit A could link the set to other sets, field phones or a switchboard. Like most early British radios, changing between ‘send’ and ‘receive’ was accomplished by operating a large switch on the set (the big white one) rather than a pressel switch on the microphone.

Size was 8-1/2” tall, by 12” deep by 19-1/2” for the set and each of the LP and HP units added another 4-1/2” each to the width. Weight for the complete station was 216 lbs. (or 180 lbs. with just the Low Power unit), Frequency coverage was 4.2 to 7.5 MHz, range from 3 miles R/T voice on low power up to 20 miles CW (Morse) on high power. Power supply was most commonly 6 volt lead acid batteries, however 240 volt dry batteries or a rotary converter could also be used.

Ladies and gentlemen, I present to you the famous Wireless Set No.11.