Summary: Army Instructional film describing aspects of the Thunderbird surface to air missile system. The film describes the interaction between missile, radar and control caravan, and communication with higher command. The use of radar to assess a target's range, bearing, elevation and height is explained, including reference to Doppler radar systems. The use of a Digital Data Transmission System to pass information between command and control elements is described in detail, referring to binary code and the equipment used to decode transmissions. Resupply of missiles from the manufacturer through the Royal Army Ordnance corps (RAOC) to the frontline units, is also covered.