Certain Factors Affecting the Gain of Directive Antennas

H R O U G H O U T the development of radio c o m m u n i c a t i o n the engineer has aspired to a directive system whereby radiation m i g h t l>e projected from one point to another with a m a x i m u m of efficiency and a m i n i m u m of interference with adjacent stations. Also, he has aimed at similar directivity at the receiver to improve the signal-to-noisc ratio a n d otherwise discriminate against undesirable signals. It was recognized at a very early date t h a t directive radio based on wave interference was feasible provided sufficiently short waves could be utilized, a n d as a result m a n y interesting suggestions to this end were made. However, as is well known, the early development of the radio spectrum proceeded in the direction of long · Presented at C o n v e n t i o n ot I. K. E, Toronto. O n t . , C a n a d a , AUK. 19, 1930. Proe., /. R . £ . . Sept. 1930.