A never ending quest for the optimum 6m antenna led me to try a Loop Fed Array Yagi. This design, pioneered by Justin Johnson, G0KSC, claims lower noise and a better 50 ohm impedance match than conventional Yagis by using a loop for the driven
element. Justin has many designs featured on his website but cautions builders that his published SWR curves are based on his
use of the NEC-4 (Numerical Electromagnetics Code) modeling engine. Since my EZNEC 4 antenna software uses the NEC-2 engine I
decided to build one of his designs that modeled well on my software. Additionally, I was eager to try out my new Christmas
present, a YouKits model FG-01 antenna analyzer.
The Yagi has a 15’-9” boom and breaks down into pieces no longer than 66” for portability. The mast is 1-1/2” square aluminum, with 5/8” OD and ˝” OD aluminum tubing elements. The EZNEC 4 model predicts a free space gain of 11 dBi with a front–to-back
ratio of 22.5 dB at 50.150 MHz. When mounted at a 25 foot elevation, the gain and front–to-back ratio are predicted to be 16.2
dBi and 25.2 dB, respectively. The modeled LFA delivers an outstanding 50 ohm match with an average impedance of 50.01 – j0.86
ohms from 50 to 50.5 MHz.
