Collinear phased 5/8 wave with two coaxial chokes to suppress cable radiation. 6dB gain. This professional quality antenna is a performance powerhouse. It's extra strong - sturdy enough to be self-supporting, even in high winds and high speeds. Brass and copper elements, stainless steel ferrule with standard 1"-14 thread, 20' RG-8/X low-loss cable plus a PL-259 connector. Two sections: base 75", tip 39". Suggested mount: use only 4187-HD ratchet mount for self-supporting applications, or use 452 mounting kit if an upper support bracket installation is preferred.