On Apr 3, 3:42*pm, Wimpie wrote:
It seems from your graph that the electrically half wave (180 degr)
helical has slightly more gain than the physically and electrically
quarter wave (90 degr) radiator (5.61 dBi for the helical versus 5.14
dBi for the quarter wave whip).

A full-length half-wave monopole has gain over a full-length 1/4WL
monopole because the current maximum point on the half-wave is
elevated by 1/4WL. The same concept has to be a technical fact for the
helical even though muted by the smaller physical distance between the
current maximum points.
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73, Cecil, w5dxp.com