A Low-Noise 'Urban' 6 element LFA Yagi for 50MHz
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 in order to minimise the upward and downward lobes typically seen the the EL plane on Yagi antennas. By doing this, a drastic reduction in pick up of unwanted noise in City locations is the result. The double bonus is the likelihood of reducing transmitted interference too. However, this version is not a model with optimum supression which would see a reduction in forward gain of 1dB. If you suffer with very bad noise on 70MHz and have room for an antenna of this size, Email me for details of the very high suppression version.
Note: There are TWO versions of this antenna below. One using Metirc tube sizes, the other using Imperial so anyone anywhere should be in a position to build this.
A 6el 50MHz LFA and a 7el 70MHz LFA at PA2J
Installed at JA2DDN
The 6el 50MHz LFA installed at EA6BB
The 6.8m Long 6el LFA installed at ZS6JON with a 6el 5.32m long 4m LFA on top
K7JA built his 6.8m 6el 50MHz LFA out of 'copper and wood' and still sees a flat SWR with super pattern !!
Built by KG4HG, Orlando Florida
6el LFA at PA3GND, DXCC # 842 for 6 Meters
The PA2V 6.8m 6el 50MHz LFA
2x 6el 6.8m boom LFAs at HB9BLF
Performance European Version UK/USA Version
Forward Gain: 11.88dBi at 50.150MHz 11.87dBi at 50.150MHz
Front to Back Ratio: 27.47dB at 50.150MHz 27.51dBi at 50.150MHz
Peak Gain: 11.94dBi 11.9dBi
Peak F/B: 27.64dB 27.85dB
Bandwidth: 500KHz below 1.1:1 500KHZ below 1.1:1
Build Dimensions for European Version
Element Spacing in metres Half element Length in metres Element Notes
Reflector 0 1.483 10mm or 3/8 inch Diameter tube or solid rod
DE1 .326 1.243 13mm or 1/2 inch Tube
DE2 .87 1.243 13mm or 1/2 inch Tube
D1 1.536 1.393 10mm or 3/8 inch Diameter tube or solid rod
D2 2.964 1.355 10mm or 3/8 inch Diameter tube or solid rod
D3 4.877 1.315 10mm or 3/8 inch Diameter tube or solid rod
D4 6.867 1.235 10mm or 3/8 inch Diameter tube or solid rod
DE1 and DE2 are joined at the ends by either 10mm tube
Feed point is the centre of DE1
This antennas has been designed using 1/2 inch elements and the loop section is made of 2 x 1/2 inch lengths with 3/8 inch sections inserted into each end in order to complete the loop. The loop is feed at the back nearest the reflector. Details of the loop layout as per picture below:
Dimensions to be added shortly