Re: dipole antenna efficiency
Posted by
Geoffrey Mackenzie-Kennedy on
Jan 04, 2008; 2:56pm
URL: http://elecraft.85.s1.nabble.com/dipole-antenna-efficiency-tp458071p458121.html
Shaun Oliver <
[hidden email]> wrote:
>I was thinking of using 18 mm electrical conduit. with 2 mm spacings for
>each turn of the wire.
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The diameter is a bit on the small side for the low bands, but NM Helix
antennas working as 'quarter wave' radiators on the low bands designed for
mobile use, and whose diameter was similar, performed well when evaluated
using a proper antenna range, better than a base loaded 8ft whip. The
important consideration is that the antenna resonates within the range of
frequencies used in the band for which the antenna is designed. I have not
tried a single NM Helix with an external tuner for multiband operation nor
tried to model one using EZNEC.
Good luck!
73,
Geoff
GM4ESD
PS 'Old scribe' --- hmmmpf :-)
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