The Clansman radio family consisted of 8 main sets and two others that are part of the same numbering scheme but not, in terms of age or technology truly Clansman. The sets are
- UK/PRC-316 (formerly Larkspur A16) lightweight HF patrol set (until at least late 1970s)
- UK/PRC-319 long range HF patrol set (in service 1989)
- UK/PRC-320 HF manpack 2-30MHz 3 or 30W USB/AM/CW
- UK/VRC-321 Vehicular HF station (5 or 40W, USB/AM/CW)
- UK/VRC-322 High Power station based on 321 with 250W valve amplifier
- UK/PRC-344 UHF air to ground station
- UK/PRC-349 VHF Squad radio 36-46MHz 250mW FM
- UK/PRC-350 Light VHF manpack 30-56MHz 2W FM
- UK/PRC-351 VHF Manpack 30-76MHz 4W FM with remote/repeater facilities
- UK/PRC-352 High Power VHF manpack formed of 351 with 20W amplifier
- UK/VRC-353 Vehicular VHF station 30-76MHz 0.1 - 50W WBFM/NBFM
There was also a UK/PRC-351M which was a 351 modified for 8KHz audio bandwidth to support secure speech equipment.
The core members of the Clansman family (i.e. everything except the A16 and 319) share a number of common features:
- Digital frequency synthesis using an internal frequency standard
- Decade switch frequency selection (except RT-319 and A16)
- Use of SSB as primary operating mode on HF (except A16)
- Use of NBFM with 150Hz tone squelch on VHF
- All solid-state (except 322 power amp and 353 PA and front end)
- A new robust 7 pin pattern 104 audio connector
- Waterproof cast aluminium cases
- BNC RF connectors (except A16 and 350 which use a "mini BNC"
- Built in remote operation on 321/322, 344, 351/352 and 353
- A new AFV audio harness for VRC sets (and PRC with adapter boxes)
- A new family of 1AH and 4AH NiCad batteries and their chargers
- US X-Mode compatible digital encrypted speech using external BID/DMU boxes see http://www.cryptomuseum.com/crypto/uk/bid250/index.htm
Clansman was supported by a range of new accessories allowing a complete break with the Larkspur equipment that went before. These included headsets and handsets, ATUs, antennas, masts, test sets, secure speech equipment, RTTY terminals and power supplies. Even the coaxial cables and connectors were changed from the unique British 75 ohm system to NATO standard 50 ohm with BNC and C types. This of course required complete refitting of vehicles that remained in service after the transition. The transition itself took quite a few years, starting in 1976 with the first use on active service in Rhodesia in 1978. About half the Army had been converted by the 1982 Falklands war and many of the units that went South had to convert en route. Clansman remained in service until the early 2000s due to an abortive replacement project (Yeoman) prior to the eventual introduction of Bowman (actually anglicised US SINCGARS and Harris Falcon) sets from 2006 onwards.
In most cases (apart from the HF sets with manual ATUs) operation was "plug, play and dial a frequency" due to the decade switch tuning and the broadband antennas - although there it can be argued that the higher power output of the Clansman sets relative to Larkspur is offset by less efficient antennas.
Clansman represented a 2 generation advance in combat net radio technology for the British army, which (apart from transistors in post Larkspur 1960s HF manpacks and a limited form of crystal mixing in the A16) had retained valves and VFO tuning in Larkspur sets through the 1960s and 70s when the likes of American PRC-25 and German SEM-35 were using analogue synthesis by the mid 1960s. Internally the sets made extensive use of small scale integrated circuits - mostly TTL and op-amps - and high density packaging and are very much of the 1970s except the 319 which entered service around 1989 and is microprocessor controlled.
It is worth noting that apart from the 322 there isn't a "strategic" HF set comparable to the Larkspur era D11/R234. This partly reflects the transfer of strategic communications to the RAF although the gap was supposed to be partly filled by NCRS cabins later in the 1980s.
Apart from the effects of age and wear on the reliability of the sets the main driver for replacement was that Clansman sets are analogue fixed frequency sets whereas most NATO nations had adopted frequency hopping and 16Kbits/s CVSD digital transmission by the turn of the century. While the speech security and CVSD requirements could be addressed by external boxes (DMU for RT-353 and BID 300 for RT352M) or digital message units (TDED/MEROD and DMHD) on HF, the development of digital spectrum analysers and fast direction finding meant that a fixed frequency radio was too dangerous to use for an extended period in one place as well as being incompatible with NATO allies. The radios remain compatible with amateur standards so remain useful on the amateur bands within the limitations of slow tuning and modest power. The HF sets were built for USB, AM and CW only but are easily and economically Converted to LSB.
It would appear that at least 100,000 radios were made, mostly VHF. Most of these came out in 2007 through 2015 via the Government's vehicle disposal contractor Witham SV and made their way onto e-Bay or into the warehouses of various dealers.
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