In early and mid World War 2 period a requirement was raised for improved short range radio intercommunication facilities
between Armoured Command Vehicles (ACV) in large HQ when either stationary or on the move.
Wireless Set No. 14, initially developed for this purpose and issued in the early days of the war was not considered suitable as being too complicated and bulky.
This need was only partially filled by the "B" set of Wireless Set No. 19, due to the limited range of this set.
Development work was therefore started on Wireless Set No. 34 which was expected to give adequate facilities up to a range of 3 miles or more on the move.
However, severe design difficulties were encountered due to interference from high power sets such as Wireless Senders Nos. 12 HP, 33, SCR299A, etc.
These difficulties appeared to be insuperable and no further work was done on the development of this set.
In the Middle East a local modification of Wireless Set No. 18 was produced which enabled it to operate a small loud-speaker
at adequate volume. An amplifier was fitted in the battery compartment of the set, the whole operating off the normal vehicle battery
and providing a suitable improvised solution to the inter ACV communication problem.
Wireless Set No. 22
Owing to the critical supply position of secondary batteries for Wireless Set No. 22,
Batteries Dry HT/LT 160/7.5V (WB N(ot) I(n) V(ocabulary)) were introduced during a certain period in 1944
as an alternative. They were made up in four containers as follows:
One Container No. 1 (Battery dry HT 160 volts)
One Container No. 2 (Battery dry HT 160 volts)
One Container No. 3 (Battery dry LT 7.5 volts)
One Container No. 4 (Battery dry LT 7.5 volts)
When operated from dry batteries the Power Supply Unit No. 4 as normally used with Wireless Set No. 22
when working from a secondary battery, was not used.
It may be interesting to note that Wireless Set No. 62 (the replacement for the No. 22 Set)
was similarly modified to operate from No. 31 Set dry batteries. See the No. 62 Set section in Volume 2 of "Wireless for the Warrior"
