Sunday, May 27, 2012

21MHz 6el OWA Yagi Print

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

Revised September 2010 v1.0
Premium commercial versions of this antenna at Innovantennas


I WILL MODEL THIS ANTENNA IN ANY TUBE SIZE OR TAPER SECHDULE FOR YOU, CONTACT ME VIA EMAIL

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

Also read 'An Intro to OWA Yagis' and also 'Creating a Balun'

Antenna Layout and Construction:



Performance
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

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