GB380842A - Directional aerial system - Google Patents

Abstract

380,842. Discharge wireless signalling. STANDARD TELEPHONES & CABLES, Ltd., Columbia House, Aldwych, London.-(Assignees of Materiel Telephonique Soc. Anon. ; 46, Quai de Boulogne, Boulogne, France.) June 25, 1931, No. 18364. Convention date, Nov. 21, 1930. [Class 40 (iv).] In a directive combination comprising an open aerial and a frame aerial, the tuning controls are ganged together so as to preserve a. constant cardioid curve over a wide range of equal frequencies, and thus enable bearings to be taken on a number of different transmitting stations without entailing elaborate readjustments. The tuned circuit of the open aerial A comprises a fixed inductance LA and a bank of fixed condensers C of different values, connected in circuit by a switch S, which is mechanically linked to the tuning condenser CF of the loop aerial F. The two aerials are adjustably coupled through inductances LF, LF<1>, LA, the combined output being fed to a direction finder DF. A resistance R prevents rapid variations in phase near the critical tuning points. The bank,of condensers C may be replaced by a tapped inductance coil or a variable condenser. Re-radiation from one aerial to the other, tending to mask the critical angle, may be eliminated by providing a reverse coupling coil between the two aerial circuits.