Measurements on high-gain helical aerial and on helical aerials of triangular section

Single helical aerials with gains of over 25dB have been constructed, and the measured variation of this gain with axial length is presented. The beamwidth corresponding to this 25dB gain is approximately 5° between half-power points. From separate experiments comparing short helixes of circular, square and triangular section, the latter appears to offer a satisfactory alternative to the conventional forms of construction.