A High-Gain 6 element LFA Yagi with a 6.4 metre Boom for 50MHz

Revised 22nd January 2010 V1.0

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 6.4 metre boom length. As with all of my second generation LFA's wide bandwidth has been modeled into the antenna to ensure maximum performance without matching losses.

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

CT1GPZ has his 6.4m 6el 50MHz LFA between HF antenna wit no effect.

The 6.4m long 6LFAKYZ 6el 6m LFA sits between 2 x 11el 2m LFAs at KA0KYZ - Details of this variant are below

The 6el 6.4m boom LFA at G0CHE

Performance

Forward Gain:                                   11.63dBi at 50.150MHz

Front to Back Ratio:                           32.27dB at 50.150MHz

Peak Gain:                                        11.69dBi

Peak F/B:                                          32.43dB

Build Dimensions using 1/2 inch or 13/12mm loop 3/8 inch / 10mm parasitic elements

Element                             Spacing in metres Half element Length in metres

Reflector                                0                                                                       1.490                3/8 inch or 10mm elements

DE1                                       .298                                       (1.245)                 1.246              1/2 inch  (12mm)

DE2                                       .823                                      (1.245)                  1.246              1/2 inch  (12mm)

D1                                        1.428                                                                 1.3875                3/8 inch or 10mm elements

D2                                        2.784                                                                 1.3485                3/8 inch or 10mm elements

D3                                        4.561                                                                 1.322                  3/8 inch or 10mm elements

D4                                        6.399                                                                 1.2425                3/8 inch or 10mm elements

Notes:

DE1 and DE2 are joined at the ends by either 3/8 inch or 10mm tube when 1/2 inch or 13/12mm DE1 and DE2 are used. these end sections should be

Feed point is ALWAYS the centre of DE1

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

6el 6LFA6KYZ version using 3/4 inch elements

Performance

Forward Gain:                                   11.77dBi at 50.150MHz

Front to Back Ratio:                           33.15dB at 50.150MHz

Peak Gain:                                        11.80dBi

Peak F/B:                                          33.23dB

Build Dimensions using 3/4 inch elements

Element                             Spacing in metres Half element Length in metres

Reflector                                0                                                                       1.486                3/4 inch elements

DE1                                       .298                                                                  1.254                 3/4 inch  (end sections 5/8 inch)

DE2                                       .822                                                                  1.254                 3/4 inch  (end sections 5/8 inch)

D1                                        1.401                                                                 1.382                  3/4 inch  elements

D2                                        2.767                                                                 1.344                  3/4 inch  elements

D3                                        4.530                                                                 1.311                  3/4 inch  elements

D4                                        6.399                                                                 1.240                  3/4 inch  elements

Notes:

DE1 and DE2 are joined at the ends by either 3/8 inch or 10mm tube when 1/2 inch or 13/12mm DE1 and DE2 are used. these end sections should be

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

Excellent elevation plot too

Antenna layout showing the feedpoint (red circle) at the back of the loop closest to the reflector

SWR Plot