Accession Number:

AD0257872

Title:

CHARACTERISTICS OF A VOR ON A 200-FOOT TOWER

Descriptive Note:

Corporate Author:

NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER ATLANTIC CITY N J

Report Date:

1960-04-01

Pagination or Media Count:

1.0

Abstract:

A mobile VOR station located in a cleared area 200 feet square at one corner of a heavily wooded site was flight tested. A maximum course scalloping of plus or minus 11.5 degrees was recorded at a radius of 20 mi and an altitude of 1,000 ft. Later, a VOR antenna was erected on a 200-foot tower with a 60-foot-diameter counterpoise. Similar flight tests indicated a scalloping maximum of plus or minus 0.5 degrees. A 20-mile-radius orbital flight in the first null 1.2 degrees produced scalloping of plus or minus 6 degrees maximum. The distance range, for a receiver input signal of 5 microvolts, varied from 63 mi at 300 ft altitude to 175 mi at 9,000 ft altitude. With an antenna 200 ft above ground, while there still are objectionable course bends in the nulls of the vertical plane radiation pattern, the detrimental effect of the site on VOR performance was reduced at low elevation angles, and the low-altitude coverage was extended. This type of installation should be useful in heavily wooded terrain where a suitable site cannot be obtained for the installation of a more conventional station. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE