Accession Number : AD0787363

Title :   Rotor Effects on L-Band Signals Received by Helicopter Antennas. A Theoretical Study. Part I: Amplitude Reduction and Phase Shift. (Schielding Effect).

Descriptive Note : Final rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Schwering,F. ; DeSantis,C. M.

Report Date : SEP 1974

Pagination or Media Count : 65

Abstract : Rotor effects on L-band navigation signals received by helicopter antennas are examined theoretically. Two types of distortions are distinguished: (a) the amplitude reduction and phase shift of CW-signals due to periodic shadowing of the antenna by the rotor (shielding effect) and (b) the distortion of phase reversals assumed to occur at predetermined intervals in the incident signals. Numerical evaluations have been performed using the pertinent dimensions of a UH-1 helicopter. It was found that the shielding effect may reduce the received power by 10 dB while the phase shift does not exceed 90 degrees. (Modified author abstract)

Descriptors :   *RADIO RECEPTION, HELICOPTER ROTORS, AIRCRAFT ANTENNAS, HELICOPTERS, L BAND, RADIO SIGNALS, RADIO NAVIGATION, PHASE DISTORTION, AMPLITUDE, REDUCTION, NUMERICAL ANALYSIS

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE