High-gain loop antenna for television broad casting

The theory and characteristics of the triangular loop elements were described in Commun., 29,16-18 (Aug., 1949). This paper describes the tower construction, etc., to use 16 instead of 8 loops with 5 ft spacing giving an array height of 80 ft and a power gain of 17. To give sufficient strength, the side of the triangular supporting tower is increased from 14 to 17 in. For the 16-element array the overturning moment at the base is increased 5 times, requiring a steel increase of over 4 times to 4700 lb. In order to eliminate structural alignment difficulties, solid dielectric cables are used to feed individual loops. To avoid coupling between successive pairs, simple untuned isolation rings are inserted. A balun impedance transformer matches the aerials to the transmission line. Sound and vision signals are combined through a diplexer and transmitted from the same array. A table of array structural data is given for using from 2 to 16 loops, also photos of the complete aerial and in parts, the diplexer and graphs of field strengths.