construction inner conductor material smooth copper tube dia. 8.80±0.10 mm insulation material physically foamed PE dia. 22.20±0.40 mm outer conductor material ring corrugated copper diameter 24.90±0.30 mm jacket material PE or fire retardant PE diameter 27.30±0.20 mm electrical properties impedance 50±2 Ω capacitance 75 pF/m inductance 0.187 uH/m propagation velocity 88 % DC breakdown voltage 6.0 kV insulation resistance >5000 MQ.km peak power 91 kW screening attenuation >120 dB cut-off frequency 5.5 GHz