in the Second World War (more resilient to jamming) and the use of frequency 1 Telecommunications is a combination of the ancient Greek word 'tele' meaning far off and the Latin word 'communicare', to impart. Making Telecoms Work: From Technical Innovation to Commercial Success, First Edition. Geoff Varrall. © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. Making Telecoms Work Figure 5.1 Pye WS19 dualband short-wave/VHF radio. Reproduced with permission of the Pye Tele- com Historic Wireless Collection. hopping and spread spectrum techniques used in the military prior to their more widespread use in commercial radio systems. However, it is not unusual for innovation to flow in the opposite direction. Radio and radar systems in the Second World War borrowed heavily from broadcast technologies developed in the 1930s. When the British expeditionary force arrived in France in 1939 they discovered that the German infantry had significantly superior radio communications, using short wave for back to base communications and VHF for short-range exchanges. In the UK a rapid design project was put in place to produce a dualband short-wave/VHF radio that could offer similar capability. This has been described as 'the radio that won the war' and is certainly one of the earliest examples of a dualband dual-mode radio. The device shown in Figure 5.1 is a WS (wireless set) 19 with a separate RF amplifier No 2 producing watts of RF power. Long procurement cycles and a need to amortise costs over a significant service period can also mean that military systems remain in use for longer than civilian systems, sometimes as long as thirty years. If this coincides with rapid development in the commercial sector then 2 http://www.pyetelecomhistory.org/ Wireless User Hardware military handsets can seem bulky and poorly specified when compared for example to modern cellular phones. Additionally, the development of a radio technology for military applications does not necessarily guarantee that the technology will 