Lattice masts. The Air Defence and Air Traffic Systems (ADATS) Delivery Team has a requirement for Glass Reinforced Plastic (GRP) or composite plastic lattice masts used as a RF transparent antenna support component on various radio mast structures. The Authority is seeking to procure these masts based in general on the original supply specification but is seeking to simplify and enhance the design by using modern material technologies and explore manufacturing techniques that are less complex. The mast sections are triangular in section of face width 450mm centres and of lengths 3,020mm and 4,500mm.