Accession Number : AD0687404

Title :   DOPPLER VOR SIDEBAND ANTENNA MONITOR,

Descriptive Note : Final rept.,

Corporate Author : CHAIN LAKES RESEARCH CORP DETROIT MI

Personal Author(s) : Szewczyk, Z. I.

Report Date : JAN 1969

Pagination or Media Count : 28

Abstract : Two prototype Doppler VOR Sideband Antenna Monitor units were developed to Engineering Requirement FAA ER 330-004. The Monitor senses the failure of the Doppler VOR antenna elements by the presence of spurious modulation on the 9960 HZ sideband signal. Failure (open or short) of one or more antenna elements results in generation of harmonics of the 30 Hz reference modulation on the 9960 Hz FM subcarrier. These harmonics exist predominately in the 200 to 600 Hz range. The radiated signal was originally to be received by the Field Detector Antenna and examined for spectral purity by the Monitor, with alarm actuated when the amount of 30 Hz harmonics exceeded a predetermined amount. The monitor also incorporates a self-check function which superimposes a partial simulated failure signal on the 9960 Hz sub-carrier. This provided continuous check of the Monitor operation. Tests of the delivered equipment indicated reliable detection of the antenna open and shorted condition. An alternate self-check configuration was proposed by the contractor and delivered for evaluation. This configuration permits a significant cost reduction and performed as well as the original configuration. (Author)

Descriptors :   (*NAVIGATIONAL AIDS, MONITORS), (*RADIO BEACONS, MONITORS), ANTENNAS, RADIO NAVIGATION, DOPPLER NAVIGATION, DOPPLER SYSTEMS, VERY HIGH FREQUENCY, RADIO EQUIPMENT, FAILURE, WARNING SYSTEMS.

Subject Categories : Air Navigation and Guidance

Distribution Statement : APPROVED FOR PUBLIC RELEASE