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A Low-Noise 6 element LFA Yagi with a 6.0 metre Boom for 50MHz

Revised August 2010 V1.0

Premium commercial versions of this antenna at Innovantennas

 

The LFA design has a patent pending and all G0KSC designs are copyright. Any ham can build for their own use or those of a friend. Where profit or commerical gain exists, express permission of G0KSC must be sought.

If you suffer with noise from living in the city, this is another low-noise antenna from G0KSC

This antenna has been designed with performance in mind and provides optimum performance for the 6.0 metre boom length. As with all of my second generation LFA's wide bandwidth has been modelled into the antenna to ensure maximum performance without matching losses.

Please read the 'how to make the LFA Loop' page here

 

Installed at ZS5QM

 

Built and installed by ZL3ADT

 

 

HK4SAN presents his 6m long 6el 50MHz LFA before it is installed on his tower

 

 

XE1R standing proud with his 'just-built' 6.0m long 6el 50MHz LFA

 

 

The 6el 6.0m 50MHz LFA at SM0RCL

 

 

Kai, SM0RCL also fitted the G0KSC Antenna Balun too

 

I've used my LFA during the opening this morning to great satisfaction. I know that I could have done some
fine tuning, but this being my first Yagi, I just wanted it UP! But on the other hand, I'm quite sure that when
my Versatower gets up, it'll contain more than one of theese. And I'm really glad that you convinced me to
build the Pawsey according to the new design....

....You can consider me as one really happy user of your designs. And please feel free to use the pictures if you want to.
I could mail them to you in higher quality than the ones that I've linked to, but I'm trying to keep the webpictures somewhat
smaller for convenience and to get correct screen resolutions.'

Kai, SM0RCL

 

 

The 4.9m long 6el 70MHz LFA installed above a 50MHz version ate G8FJG - Antenna Baluns installed on both

 

Performance

Forward Gain:                                   11.21dBi at 50.150MHz

Front to Back Ratio:                         31.45dB at 50.150MHz

Stacking:

Vertical Spacing:                                4.7m

2 x Gain:                                              13.87dBi at 50.150MHz

2 x F/B:                                                 34.53dB

 

Build Dimensions using 1/2 inch elements   12mm element version below

Element                             Spacing in metres Half element Length in metres

Reflector                                0                         1.487                1/2 inch elements

DE1                                       .300                    1.258               1/2 inch  elements

DE2                                       .824                    1.258                1/2 inch  elements

D1                                        1.276                   1.4035              1/2  inch elements

D2                                        2.435                   1.3605              1/2 inch  elements

D3                                        4.106                    1.316                 1/2 inch  elements

D4                                        6.000                    1.2015               1/2 inch  elements

Notes:

DE1 and DE2 are joined at the ends by either 3/8 inch tube. Adjust width of loop for best SWR

Feed point is ALWAYS the centre of DE1

Please read the 'how to make the LFA Loop' page here

 

Version using 12mm elements

 

Performance

Forward Gain:                                   11.20dBi at 50.150MHz

Front to Back Ratio:                           32.17dB at 50.150MHz

Stacking:

Vertical Spacing:                                4.7m

2 x Gain:                                              13.86dBi at 50.150MHz

2 x F/B:                                                 35.45dB

 

Build Dimensions using 12mm elements

Element                             Spacing in metres Half element Length in metres

Reflector                                0                         1.488                   12mm elements

DE1                                       .300                    1.2615                 12mm  (end sections 8/10mm)

DE2                                       .824                    1.2615                 12mm  (end sections 8/10mm)

D1                                        1.276                   1.4045                 12mm  elements

D2                                        2.435                   1.3615                 12mm  elements

D3                                        4.106                   1.317                   12mm  elements

D4                                        6.000                   1.2025                 12mm  elements

Notes:

DE1 and DE2 are joined at the ends by either 8mm or 10mm tube. Adjust loop width for best SWR

Feed point is ALWAYS the centre of DE1

Please read the 'how to make the LFA Loop' page here

 

 

Performance plot of this fantastic antenna

 

Single antenna Azimuth Plot

 

 

Single Antenna Elevation Plot

 

 

Single antenna 12m up over average ground

 

 

2 x 6el (stacked 4.7m apart) with bottom antenna at 12m up

 

 

Single Antenna SWR Plot

 
 
 
 

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