LONG DISTANCE VHF/UHF COMMUNICATIONS GROUND ANTENNA ARRAY.
PAGE COMMUNICATIONS ENGINEERS INC WASHINGTON D C
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A dual VHFUHF antenna for ground-to-air extended range communication was developed. The antenna contains a 32 dipole VHF array 127-136 mHz and a 32 dipole UHF array 277-329 mHz in a 60 degrees screen corner reflector. The antenna including reflector is supported by a triangular guyed steel tower with a nominal 15-foot cross section. The supporting tower is 225 feet high. Each array is fed by a 50 ohm transmission line harness forming a binary corporate structure. The harness uses standard 78 in. and 1-58 in. flexible air dielectric 50 ohm cables and contractor-developed binary power dividers. The complete transmission line harness, binary transformers, and dipole feed points are pressurized with dry air from a dehydrator. This antenna has been installed at a site with an elevation of 6,600 feet on Mt. Haleakala, Maui, Hawaii. The main radiation lobes of the antenna are aligned on a bearing of 56 degrees true so as to center the beams on the Mainland - Hawaii air routes. The radiation lobes of the antenna are electrically tilted -1.05 degrees below the site horizontal to align the beam nearly on the site horizon. The tilt angle has been chosen to provide a horizon clearance of 0.2 plus or minus 0.1 degree. The electrical tilt is provided by graded length cables in the binary harness at the feed points for each group of four dipoles. Author
- Electrical and Electronic Equipment
- Air Navigation and Guidance