Accession Number : AD0886343

Title :   LF to VHF Shipboard Direction Finding Research.

Descriptive Note : Final rept. 8 Jun 70-8 Jun 71,

Corporate Author : SOUTHWEST RESEARCH INST SAN ANTONIO TX

Personal Author(s) : Green, Terry C. ; Sherrill, William M.

Report Date : 08 JUN 1971

Pagination or Media Count : 33

Abstract : An FET/varactor diode tuning circuit was designed and developed for use with an existing ferrite core crossed spaced loop antenna. Sensitivity and antenna patterns were obtained for the ferrite antenna over the tuning bandwidth of 2 to 32 MHz. Matched tuning circuits were developed to provide tuned ferrite spaced loop direction-finding capability. DF performance of the tuned ferrite antenna showed undesirable DF characteristics due to mutual coupling and poor tracking from element to element. DF evaluation of a prototype air core crossed spaced loop antenna using the previously developed tuning circuits showed improved performance compared to the ferrite antenna. Additional techniques for spaced loop sensitivy improvement were investigated, including the use of multiturn loop elements and capacitive loading of electrostatic shield gaps. (Author)

Descriptors :   *LOOP ANTENNAS), (*DIRECTION FINDING, TUNING DEVICES, HIGH FREQUENCY, MAGNETIC CORES, TUNED CIRCUITS, SHIP ANTENNAS.

Subject Categories : Direction Finding

Distribution Statement : APPROVED FOR PUBLIC RELEASE