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21MHz 7el OWA Yagi

A 7 element OWA Yagi for 21MHz with a 16.3mtr boom

Revised August 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 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. It has options with both UK/USA and European sized tube and has a 3 section taper.

This Antenna has been modelled using NEC4 and confirmed by FEKO. This is thousands of dollar 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.

 

Also read 'An intro to OWA Yagis' and 'Creating a Balun'

 

Antenna Layout and Construction:

 
 

Performance

11.89dBi @ 21.200MHz

23.86dB @ 21.20MHz

SWR: Below 1.1.1 from 21MHz to 21.450MHz

 

Construction details

 

Refer to the above drawing.


Antenna Dimensions for UK/USA sized tubing - European version below

Taper: Mid Section, 5/8 inch tube (total length 4.8m). Outer section 1/2 inch 2.4m long. End sections as per below schedule

 

                          Spacing                  End Section Length   (All below sizes in Metres)               

Reflector                0                              1.201                                          

DE1                      2.064                        1.133                                           

D1                        2.798                           .964                                           

D2                        4.881                           .948                                           

D3                        8.150                           .879                                           

D4                        12.452                        .820                                           

D5                        16.835                        .666                                           

 

 

Antenna Dimensions for European sized tubing

Taper: Mid Section, 16mm tube (total length 4.8m). Outer section 13mm tube 2.4m long. End sections as per below schedule

 

                         Spacing                      End Section Length  (All below sizes in Metres)          

Reflector                0                              1.199                                            

DE1                      2.064                         1.130                                             

D1                        2.798                          .962                                             

D2                        4.881                         .946                                             

D3                        8.150                         .877                                             

D4                      12.452                         .818                                             

D5                      16.835                         .664                                            

 

 

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

 
 
 
 

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