Sunday, May 27, 2012

28MHz 6el LFA Yagi

A 6 element LFA Yagi for 28MHz with a 11.960mtr boom

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 is a high-gain, wideband LFA (Loop Fed Array) Yagi which covers 28 - 28.5MHz with an SWR of less than1.3:1. 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 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 or require different element diameter.

Also read 'An Intro to LFA Yagis' and 'Making the LFA Loop' and 'Creating a Balun'

Antenna Layout and Construction:




Performance
11.97dBi @ 28.250MHz
26.96dB @ 28.250MHz
SWR: Below 1.3.1 from 28MHz to 28.500MHz

Construction details:

Refer to the above drawing.

Antenna Dimensions for UK/USA sized tubing - European version below
Taper: Mid Section, 5/8 inch or 16mm tube (total length 1.828m). Outer section 1/2 inch or 13mm tube. End sections as per below schedule and in 3/8 inch or 10mm.

                             Spacing                  End Section Length (All below sizes in Metres)
Reflector                0                               .739
DE1                         .598                        0.275 - FEEDPOINT
DE2                       1.577                        0.275
D1                         2.807                        0.565
D2                         5.384                        0.503
D3                         8.591                        0.459
D4                       11.960                       0.340
Adjust loop width for best SWR upon completion. Fit antenna with a 1:1 balun
 

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