A High-Gain 6 element LFA Yagi with a 6.4 metre Boom for 50MHz
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 6.4 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 in the Construction Menu.
2 x 6.4m 6el at VK6OX
2 x 6.4m long 6el 50MHz LFAs at ZL1RS
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
Stacking Version of this Antenna using UK/USA sized material
Performance
Forward Gain: 11.45dBi at 50.150MHz
Front to Back Ratio: 34.31dB at 50.150MHz
Peak Gain: 11.47dBi
Peak F/B: 35.23dB
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 1.487 3/8 inch elements
DE1 .298 1.249 1/2 inch
DE2 .826 1.249 1/2 inch
D1 1.326 1.405 3/8 inch elements
D2 2.578 1.3625 3/8 inch elements
D3 4.377 1.317 3/8 inch elements
D4 6.399 1.2265 3/8 inch elements
Notes:
DE1 and DE2 are joined at the ends by 3/8 inch 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
Version using 10/12mm elements
Performance
Forward Gain: 11.44dBi at 50.150MHz
Front to Back Ratio: 34.85dB at 50.150MHz
Peak Gain: 11.45dBi
Peak F/B: 35.40dB
Build Dimensions using 3/4 inch elements
Element Spacing in metres Half element Length in metres
Reflector 0 1.4865 10mm elements
DE1 .298 1.252 12mm (end sections 8/10mm)
DE2 .822 1.252 12mm (end sections 8/10mm)
D1 1.401 1.4045 10mm elements
D2 2.767 1.362 10mm elements
D3 4.530 1.3165 10mm elements
D4 6.399 1.226 10mm elements
Notes:
DE1 and DE2 are joined at the ends by either 8 or 10mm tube. these end sections should be adjusted for best SWR.
Feed point is ALWAYS the centre of DE1
Please read the 'how to make the LFA Loop' page here
Stacking distances (Both versions):
Best Pattern (lowest noise): 4.8m
Gain: 14.06dBi @ 50.150MHz
F/B: 35.37dB @ 50.150MHz
High Performance: 5.2m
Gain: 14.21dBi @50.150MHz
F/B: 34.17dBi @ 50.150MHz
Azimuth Plot of this 6el LFA Stacker
And now the single Antenna Elevation plot
Freespace elevation plot at 4.7m spacing
Freepsace plot at 4.8m spacing
Freespace plot at 5.2m spacing
Elevation plot with 4.7m spacing at 12m above ground (bottom antenna)
Elevation plot with 4.8m spacing at 12m above ground (bottom antenna)
Elevation plot at 5.2m spacing at 12m above ground (bottom antenna)
Azimuth plot when 2 antennas are stacked
SWR Plot for this antenna
