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This heavy duty antenna tuner, built by E. F. Johnson in the late 1950s, will would be a rare find and a handsome addition for a collector. This Johnson KW matchbox is fully tested and works properly. The SWR meter with the directional coupler (bridge) and a copy of the manual are included. The Matchbox is rated up to one-kilowatt (AM, maximum input to the final amplifier) and couples a 52-ohm coaxial transmitter output to antenna loads that range from 50-ohms to 1200-ohms for balanced lines and 50-ohms to 2000-ohms for unbalanced lines. It's designed to handle all modes of transmission at today's legal power limit. This antenna coupler (tuner) circuit consists of a parallel resonant network with an inductor and a coaxial wound coupling link, a dual tuning capacitor, and a dual differential matching capacitor. Unlike most tuners that are presently available, this is a real balanced antenna tuner (no ferrite core balun). It can also be used as an unbalanced tuner for matching coaxial cables. The unit measures 17.25" x 12.125 x 10.875" and weighs 27 lbs. (Immaculate johnson kw matchbox with swr was posted and is owned by: Faye Rodriquez) |
F.Rodriquez@chicagopartsnetwork.com (Faye Rodriquez) for more information.
