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The HF Wniloop antenna is a new electrically-small tunable one-turn loop for high-power (1 Kw, C. W.) transmitting and receiving in the HF communications hand (3-30 MHz). It exhibits a good impedance match to a 50-ohm transmission line at resonance over an 8:l tuning range, constancy of radiation pattern, and high over-all performance.A single remotely controlled high-Q vacuum capacitor, which is an integral part of the antenna itself, is the only variable r-f component involved in t uni ng.The HF Miniloop is considered to he an optimum design for a miniature antenna. The small size and surprisingly high efficiency render it, in effect, a tuned filter which enhances the signalhoise characteristics on receiving, and makes duplex communications eminently pratical. Part of the relative immunity to local interference derives from the inherent electrical balance to ground. The antenna is grounded to its support mast at its neutral point, and is preferably installed at low heights above ground.The paper describes these and other interesting features, including ease of installation and siting in difficult environments, excellent shorthop communications characteristics, and automatic lock-on-and-track t uni ng. 327