[TowerTalk] Duo band 20/15 meter beam

[john at kk9a.com]

It is not too difficult to design a small interlaced multi-band beam but I
have had a lot of trouble designing a larger multibander with many
elements. Kudos to Yagi designers like N6BT, DF2BO, G0KSC.

John KK9A


To:	towertalk at contesting.com
Subject:	Re: [TowerTalk] Duo band 20/15 meter beam
From:	"Joe Subich, W4TV" <lists at subich.com>
Date:	Thu, 3 Nov 2016 16:26:19 -0400

Yes, Force 12 has done it for years.  The C3 series of antennas are
overlaid 2 elements for 20/15/10 meters with parasitic coupling from
the 20 meter DE to the 10 and 15 meter DEs.  The general concept of
the C3 is documented in the ARRL Antenna Book (23 rd Edition) pages
11-27 and 11-28.

There are several other examples of the technique.  It is rather easy
to design such an antenna - typically DE/Ref for 20 and 15 and DE/Dir
for 10 meters - with modelling software.

Specific dimensions will depend on the diameter of the tubing used
and mounting/insulating methods.

73,

   ... Joe, W4TV