A radio wave is an electromagnetic transmission composed of electric and magnetic fields vibrating together. Whereas light is characterised by wavelength, radio waves are usually described by the inverse of wavelength: frequency. The frequency at which a radio wave cycles per second is measured in units of ‘hertz’. Radio signals can either be omnidirectional and propagate outward in a spherical shape, or they can be unidirectional and radiate outward as a focused beam.
Combat net radio systems are typically used for command control in combat e.g. for tactical communications between armoured vehicles and infantry at section and platoon level upwards. Typically they have a press-to-talk PTT ‘half-duplex‘* functionality using either a single radio frequency or a defined set of frequencies. Such spread-spectrum radio sets are both difficult to jam or intercept and can share a frequency band with many other transmitters with minimal interference. Clansman is a combat net radio system with these characteristics, and was developed from Larkspur, which was the first combat net radio system used by the British Army with its HF C13 and VHF C45 sets. During the lifetime of the Ferret, both Larkspur and Clansman were in use. Many vehicles, such as 01 DC86, were retrospectively upgraded to Clansman with the dual radio/intercom harness that Larkspur lacked.
Developed in the mid-1970s** and after a phased introduction into service by 1978, the Clansman range of equipment was first deployed on a major campaign in 1982, when it proved effective in providing reliable communications during Falkland Island operations against Argentinian occupying forces, being more flexible, reliable and far lighter than Larkspur. The technological advances of the Clansman design allowed the introduction of Single Side Band (SSB) operation and Narrow Band Frequency Modulation (NBFM) to forward area combat net radios for the first time.
The Clansman family ( a summary is given here) of radios comprises nine sets, of which three are vehicle-mounted, and the other six man-portable. These are designated ‘UK/VRC’ or ‘UK/PRC’, which stand for ‘United Kingdom/Vehicle Radio Communications’ and ‘United Kingdom/Personal Radio Communications’ respectively. Essentially, VHF gives short range line-of-sight communications, whilst HF is used for longer distances. Two radios were principally used in the Ferret: (a) the PRC 351/352 – an intra-platoon level backpack VHF FM transceiver and (b) the VRC 353 – a vehicle-mounted VHF FM transceiver with the same frequency range as the 351/2 but greater power and potentially longer range. The radios fitted to the Ferret would be dependent upon its role of liaison & reconnaissance. The sidebar on the right describes the Clansman range, while the Intercom & ANR page explains more about working audio comms.
Clansman was superceded by Bowman from April 2005 which was first used in Iraq by the 12th Mech. Brigade. This latest combat net radio provides the British Army with an integrated digital communications network from formation headquarters forward to the fighting units having HF, VHF and UHF voice & data communications and GPS capability. The latest (2013) Bowman upgrade is BCIP 5.5; despite General Dynamics giving a favourable report on their website, Bowman was said to contain many faults (Parliamentary report) to the extent that troops dubbed it “Better Off With Map And Nokia”. In 2016 the next generation combat telecommunications system, Morpheus, was announced. Clansman is now used by civilian enthusiasts. The permitted frequencies are given here, as well as in the notes on Clansman combat net radio in the sidebar on the right.
- Steve Slack – http://www.clansman-radio.co.uk/radios.html (for equipment)
- M0VST amateur radio pages (for information)
- G8JNJ amateur radio pages (for information)
- Former Larkspur and military AM radios and Set No 19 group (for information)
- From Larkspur to Clansman: Part 1
- From Larkspur to Clansman: Part 2
- UK Vintage Radio forum and Radionerds
- UK/VRC-353 Technical description and manual
- Operation & harness diagrams PRC 351/2 VMARS Newsletter on the PRC 351/2
- Understanding Antennas also Cadet Signals (see Equipment pull-down) Wikipedia entry Clansman description and Ground Spike
- Starting in amateur radio and Radio Society of Great Britain (Club finder)
- Clansman radio user and installed for civilian use
* In a half-duplex system, each party can communicate with the other but not simultaneously. The communication is in one direction at a time to conserve bandwidth. For example, a walkie-talkie requires only a single frequency for bidirectional communication, whereas a mobile phone, a full-duplex device, requires two frequencies to carry the two simultaneous voice channels, one in each direction. A simplex system is a one-way Tx communicator, e.g. a wireless garage door controller.
** An article in the New Scientist dated 8th of January 1976 shows a VRC 353 set installed in a 1960 vintage Ferret, wrongly described as an ‘armoured personnel carrier’. During the ‘Troubles’ a Ferret would travel in convoy behind the CO/RSM’s FFR landrover, which was fitted with a BID/150 speech encryption unit for Larkspur (the BID250 & DMU were the later Clansman equivalents and the encrypted radios had the suffix Z added to their name). Although it never happened, the role of the Ferret upon the convoy being attacked was to fire at and destroy the BID/150.