THIS IS THE GENUINE JSC DR-450S, LOW LOSS, BLACK
Full Reel approximately 328Ft/100 metres.
Ladder Line, twin-conductor, flat cable used as a transmission line to carry radio frequency (RF) signals.
Constructed of two multi-stranded copper-clad steel wires, held a precise 22mm apart by a plastic-sheathed ribbon. The polyethylene webbing between the wires which holds them apart has rectangular openings called ‘windows’ cut in it, with a conductor spacing of about an inch. The advantage of the windows is that they lighten the line, and also reduce the amount of surface on which dirt and moisture can accumulate, making the ladder line less vulnerable to weather-induced changes in characteristic impedance. The plastic also covers and insulates the wires.
It is much easier to handle than traditional open wire feeder yet retains the ultra low loss feature. The uniform spacing of the wires is the key to the cable's function as a parallel transmission line; any abrupt changes in spacing would reflect radio frequency power back toward the source. This cable will handle 1kW with ease and is far superior to the common 300 Ohm ribbon type.