1840 channels spaced 25 kHz apart. This radio is also capable of being mounted on a vehicle in conjunction with the TUAAM. The PRC 352 is identical, with the addition of a 20 watt RF amplifier and can be used as a ground station. UK/VRC 353 A vehicle-mounted VHF FM transceiver built by Marconi Space and Defence Systems. The frequency range and channel separation is the same as the 351/352 with output power settings up to 50 W. Antenna systems are provided to provide improved performance in semi-static situations such as an elevated broadband vertical dipole mounted on an 8-metre mast. The VRC 353 is also capable of data transmission and when used in conjunction with an add-on unit (Digital Master Unit) provides a medium level secure speech network. The VRC 353 was notable as the only set in the Clansman family to partially employ thermionic valves - a single conduction-cooled tetrode as the transmitter power amplifier which is always in use even at the minimum 100mW power output, and two wired-in pentodes as RF amplifiers in the receiver section. It is often asserted that this was done to provide protection against Electro Magnetic Pulse (EMP) damage arising from a nuclear weapon strike, but was in fact necessary (at the time of design) in order to meet the required specification for dynamic range and adjacent channel performance. UK/PRC 346 A portable backpack or vehicle mount VHF to UHF transceiver built by Raytheon. The frequency range is 30Mhz to 390Mhz. AM and FM modes enabling compatibility with airborne units. Unusually for a military radio, it can also work in duplex modes. Power settings are 2 watts on low power and 7 watts on high. It has interfaces for GPS. Clansman UHF radio sets UK/PRC 344 A forward air control UHF AM transceiver. Built by Plessey. Operates in 225–399.9 MHz range with 50 kHz steps for a possible 3500 channels. RF power output is rated at 2.5 watts. Batteries and charging Manpack and Portable Stations. Re-chargeable batteries were supplied for all of the portable range of radios. The PRC 344, PRC 351, 351/2 and PRC 320 all shared the same common battery – the 24 Volt 3.3 ampere hour Nickel Cadmium (NICAD) type later upgraded to 4 ampere hour (or Ah), and ultimately 5 Ah due to advances in battery manufacture. Each radio would be issued with three batteries, and a range