Our extensive military collection includes radio equipment from World War I and II. We are lucky to have some sets from the estate of Donald Hings, a local Burnaby man who invented the ‘Walkie Talkies’, sued ‘the king’ and won!
The military was one of the first ‘markets’ for radio equipment: the early experimental tube types were developed to act as repeater amplifiers for telegraphy use, and ship-to-ship and ship-to-shore transmitter and receiver equipment was developed for use on navy ships prior to WWI. During the 1914-18 conflict, the use of radio became widespread and the military started to pump money into this new technology, so by the end of WWI radio transmitters and receivers were in everyday use by the army, navy and air force. Radio technology improved in leaps and bounds immediately after WWI, with many new circuit innovations and development of new and improved tube types for both receiver and transmitter applications.
By WWII, hand-held ‘walkie-talkies’ had been developed, along with VHF and UHF communications techniques, as well as simple radar equipment. WWII saw another rapid phase of radio development driven by military needs, including the development of miniature tubes and completely new tube types such as the multiple-cavity magnetron (‘the tube that won the war’) for high-power microwave (high definition) radar systems. This development continued through the Korean and Cold War eras and beyond, tube sets eventually giving way to sophisticated solid-state technology. By the time tube sets were finally exiting production in the early-mid 1970’s, most of the failings of early solid-state receivers had been resolved… but tube radios had (have) one additional bonus for military use, they are relatively ‘bomb proof’ (literally). ‘Hardened’ receivers were developed to mitigate EMP (electro-magnetic pulse) damage, such as released by a nuclear explosion, which can destroy solid-state receivers in a fraction of a second. Also, it is reported that tube radios were used in ‘Operation Desert Storm’ in the 1990’s as military solid-state sets of the time could not cope with the high levels of static discharge generated by hot, dry sand moving at speed across the vehicle aerials (acting like a Wimshurst machine).
But what sets radio equipment designed for military applications apart from commercial communications receivers? A number of things: dependability is very high on the list, which means things like ruggedized construction, use of high-quality parts (‘mil spec’), robust mechanical design and tropicalization (protection against fungal growth), high performance (good sensitivity and selectivity in receivers), portability, ease of servicing in the field (eg. by modular design), ability to operate from a variety of power sources, ease of operation, etc, plus rigorous pre-manufacturing test programs. All of these things add a considerable cost premium to the equipment (that’s one reason our taxes are high!).
The SPARC museum has a whole section, the ‘Foxhole’ – devoted entirely to military radio equipment, from transceivers manufactured in Canada for use in tanks on the Russian Front in WWII, through racks of Canadian Navy radio equipment to transmitters and receiver/direction-finding equipment from bombers.