A short 5 element LFA Yagi for 50MHz with a 4.6mtr boom
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 suppression which would see a reduction in forward gain of 1dB. If you suffer with very bad noise on 50MHz and have room for an antenna of this size, Email me for details of the very high suppression version.
This antenna can be built with Metric or Imperial sized tubing:
A 5el 4.7 mtr LFA on test at G0KSC
Martello Tower Group have the 5 element 4.7mtr 50MHz LFA and a 9el 4.5mtr 144MHz LFA
2 x 5el at OE9ICI
Gain: 10.82dBi @ 50.150MHz
F/B: 23.84dB @ 50.150MHz
Peak Gain: 10.83dBi
Peak F/B: 25.28dB
SWR: Below 1.1.1 from 50MHz to 50.600MHz
Spacing Half Element Size in Metres Element Diameter
Reflector 0 1.483 10mm or 3/8 inch
DE1 .317 1.243 (1.240 for 12mm Tube) 13mm or 1/2 inch
DE2 .865 1.243 (1.240 for 12mm Tube) 13mm or 1/2 inch
D1 1.461 1.396 10mm or 3/8 inch
D2 2.853 1.353 10mm or 3/8 inch
D3 4.565 1.298 10mm or 3/8 inch
The ends of DE1 and DE2 are connected together with 10mm or 3/8 inch tube. the Feed point is the centre of DE1.
NOTE: SWR will not read as per the graph below if you use a package with mininec or nec2 the swr graph is correct and confirmed within nec4 and through building this antenna.
Any questions, please ask!