xuedian Antenna Systems Lightweight Telescopic Masts are designed for xuedian weights up to 15 kg at a maximum height of 12 metres. The masts are light, reliable and simple to erect. Two versions are available: • Series 400, manually operated (push-up) • Series 700 pneumatically assisted The pneumatic masts can be extended using either a foot pump or an electric pump. Manufactured from high tensile aluminium alloy, the standard 8, 10 and 12 metre masts are composed of eight sections to ensure a combination of minimum weight, minimum retracted height and maximum strength. The 9 metre mast is designed specifically to support antenna arrays, such as xuedian Antenna Systems Type 752 VHF Log Periodic (30 MHz to 88 MHz) antenna. This mast has four aluminium lower sections and a GRP top section. The (non-metallic) top section reduces radiation pattern distortion caused by the mast proximity when using vertically polarised antennas. When extended, each mast section is positively locked in its full or partially extended position by a specially designed friction clamp. The friction clamp is a particular feature of this type of mast and provides a positive self-aligning clamping force actuated by a lever forming part of an over-centre toggle arrangement. Another important feature of masts of this type is the damping effect during retraction. The rate of fall during retraction is controlled by a pneumatic damping system which ensures the safety of the operator and the mast head equipment. The retracted mast (nested) is supported on the base plate using the erection guys. The top section clamp is then unlocked, the top section erected and the clamp re-locked by closing the clamp lever. This procedure is repeated for subsequent sections until the mast is fully extended or until the required height is reached. The mast is lowered by unlocking the bottom clamp and allowing the mast to retract under its own weight. Subsequent clamps are unlocked similarly until the mast is fully retracted. The piston seals are designed to give sufficient cushioning effect during retraction, while imposing minimal drag during manual extension. All masts are precision engineered and manufactured to meet the most exacting requirements of modern communications. Although primarily for military use to support various types of antenna, the masts are used in a wide range of alternative applications, including support of CCTV cameras, public address loudspeakers, floodlights and emergency lighting for airfields and construction sites. The standard colour is anodised green; optional colours of black and sand are available on request. Mounting kits are available for ground, vehicles and shelters, and a variety of ancillary equipment.