MFJ-1979 Antenna, telescopic, 20m Base of each whip features a standard ? - 24 mounting stud for installation on mobile or fixed antenna mounts 16.9 feet fully extended Telescopes for full  Wave operation on 20 Meters without loading coil and 30 / 40 / 60 / 80 / 160 Meters with loading coil. Collapses to 27 inches ? inch diameter by 2 ? inch long chrome plated brass base