SD, S is coaxial cable, D is air. This cable is mainly applied to radio and television transmission systems and radar systems, the main features are: transmission power, low loss. The inner conductor is more dimensioned with copper-plated aluminum, copper wire, brass, brass brass, sheath PE is polyethylene, generally used at 1GHz.
SDY: S coaxial cable, D is the air cable, Y polyethylene, collectively referred to as polyethylene thread insulated corrugated copper outer conductor coaxial cable, the series is mainly used for medium wave, FM, TV transmitter, satellite ground station, radar Or other high-frequency another as a low-attenuation, high-power signal transmission line. Features: power transmission large, low loss, the conductor, copper, brass, brass brass, insulation: spiral PE, polyethylene. Generally use 3 G below