Canvey Island, Essex, England
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Twin boom quad
144MHz LFA Yagis
144MHz LFA Yagis

Low Noise LFA Yagis designed by G0KSC free to build for personal use.

144MHz LFA Yagis
70cms LFA Yagis
70cms LFA Yagis
Twin-Boom G0KSC Quads
G0KSC Twin-Boom Quads
Twin-Boom G0KSC Quads
G0KSC Custom Dish feeds - Above installation @ HB9Q
Custom low-noise dish feeds
Custom low-noise dish feeds
G0KSC Custom Dish Feeds

Above installation @ HB9Q

G0KSC Custom Dish feeds - Above installation @ HB9Q
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21MHz 6el OWA Yagi

A 6 element OWA Yagi for 21MHz with a 14.785mtr boom - 6OWA21OS

Premium commercial versions of this antenna at Innovantennas


This antenna was designed for 9A3OS

This is a high-gain, wideband OWA (Optimised Wideband Array) Yagi which covers the whole of the 15m band with an SWR of less than1.1:1 from 21-21.45MHz. It is a non-crtical antenna so both metric and imperial sized tubing can be used with the same dimensions. This antenna has a three stage taper.

This Antenna has been modelled using NEC4 and confirmed by FEKO. This is thousands of dollars of the very latest antenna design software available and the results are highly accurate. When loading into your software, you will see similar SWR but not the same. Please do not alter the model, build to these dimensions for the best results.

Contact me if you are unsure what correction (if any) you require for the element holders/stand-offs you will use or any other questions you may have.

The 6OWA21OS by Eantennas of Spain (produced under license)

2 x 6el 21MHz G0KSC OWA Yagis installed at 9A7A contest station

'Onyl tried 15m stack, because we were to tired being out on the field all day long.

If I say a 15m is fenomenal, that would simply be an understatement. I've worked a tone of NA,they where calling and calling ... :-)
The pile up was really huge.'
Sam 9A3OS

Antenna Layout and Construction:


11.71dBi @ 21.225MHz

20.88dB @ 21.225MHz

SWR: Below 1.1.1 from 21MHz to 21.450MHz

Construction details / Taper schedule

Refer to the above drawing.

European version tube diameter

Mid Section: 25mm, Outer Section: 20mm, End Sections (as per details below)

UK/USA version tube diameter

Mid Section: 1 inch, Outer Section: 3/4 inch, End Sections (as per below schedule)

Antenna Dimensions For either UK/USA sized tubing or European/metric sized tubing

                              Spacing                  End Section Length   (All below sizes in Metres)

Reflector                0                             1 .303

DE1                      2.062                       1 .225

D1                        3.281                        1.055

D2                        6.366                         .996

D3                      10.888                        .930

D4                      14.785                        .862

Polar Plots

Azimuth Plot of this super antenna

Elevation plot of this antenna

Elevation plot of this antenna at 15M above ground

SWR Plot

Any questions, please ask!

Justin G0KSC