Sunday, May 27, 2012

28MHz 5el LFA Yagi

A 5 element LFA Yagi for 28MHz with a 8.2mtr boom - 5LFA10HZE

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 LFA (Loop Fed Array) Yagi which covers 28 - 28.5MHz 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. It was designed for CT1HZE and now available for all to use.
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.

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

Antenna Layout and Construction:




Performance
10.73dBi @ 28.250MHz
20.26dB @ 28.250MHz
SWR: Below 1.2.1 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 tube (total length 1.2m). Outer section 1/2 inch 1.1m long. End sections as per below schedule

                          Spacing                  End Section Length (All below sizes in Metres)
Reflector                0                              1.026
DE1                         .483                        0.550 - FEEDPOINT
DE2                       1.453                        0.550
D1                         2.492                         0.852
D2                         4.839                         0.766
D3                         8.178                         0.632
Adjust loop width for best SWR upon completion. Fit antenna with a 1:1 balun


Antenna Dimensions for European sized tubing
Taper: Mid Section, 16mm tube (total length 1.2m). Outer section 13mm tube 1.1m long. End sections as per below schedule

                           Spacing                      End Section Length (All below sizes in Metres)
Reflector                0                              1.022
DE1                         .483                        0.547 FEEDPOINT
DE2                      1.453                         0.547
D1                        2.492                         0.848
D2                        4.839                         0.762
D3                        8.178                         0.628
Adjust loop width for best SWR upon completion. Fit antenna with a 1:1 balun

Stacking distance: 8m
Gain:                          13.42dBi
F/B:                             20.40dB

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