GB682274A - Improvements in or relating to aircraft receiving antennae - Google Patents

Abstract

682,274. Aerials; aerial coupling arrangements. DECCA RECORD CO., Ltd. May 9, 1951 [May 10, 1950], No. 11690/50. Classes 40 (v) and 40 (vii). An aircraft receiving aerial for low-frequency omni-directional reception comprises an upright conducting element and a shield member, earthed either directly or through a small impedance to the aircraft body, disposed in front of the conducting element and partially surrounding it to reduce static interference due to charged particles of dust or rain impinging upon the conducting element. In the preferred embodiment the aerial comprises a vertical blade 14 coupled to the input of an amplifying stage 15 preceding the receiver 16. The aerial conductor 14 is mounted within a mart 12 of insulating material, which prevents the production of interference by corona discharge, mounted upon the fuselage 10 of the aircraft. A conducting shield 13 constructed of metal sheet or gauze is arranged around the leading edge of the mast 12 and as shown, is attached to the inner surface thereof though it may alternatively be attached to the outer surface or embedded within the material of the conductor. In the arrangement shown the shield is not directly earthed to the body of the aircraft but is connected to a point in the cathode circuit of the valve 15, the feed-back produced thereby reducing the potentialdivider effect produced upon the received signal by the capacity between the conductor 14 and shield 13. Also, in this arrangement, high-frequency chokes 19 and 20 having a low-impedance to the low-frequency signals received by the aerial conductor 14 are connected in the leads from this conductor and the shield 13, whereby the shield may be used as an aerial for receiving very high-frequency signals which are applied to receiver 22.