EAntenna 144XLFA 144 MHz cross yagis

Technical description

A cross yagi consists of two normal yagi systems mounted on the same boom and rotated 90° in position.

The EAntenna 144XLFA series cross yagis also feature LFA dipoles. LFA yagis differ significantly from traditional yagi designs.

The LFA ("Loop Fed Array") has a rectangular dipole with 1λ length. The dipole lies flat on the boom in the same plane as the parasitic elements. The outer sides of the dipole run parallel to the boom and are designed to be exactly in phase opposition (±180°).

This causes signals on these sides to cancel each other out, resulting in significantly reduced side lobes, low G/T values and a better front-to-back ratio.

LFA Yagis have 50Ω impedance and do not require lossy transformations. 

The antennas have one connector each for horizontal and vertical polarisation.

Application description

The 144XLFA antennas are excellently suited for EME applications. We offer the antennas with boom lengths ranging from a still quite compact 3.25 m to the "full size" variant with 2 x 16 elements at a boom length of 11.17 m. With the latter, fabulous gain values can be achieved. With the latter, fabulous gain values of up to 23 dBi (e.g. at an installation height of 10 m above ground) can be achieved. 

Either both systems (both dipoles) are controlled via one signal, but with different phases, thus achieving circular polarisation. For this purpose, the X-position of the antenna is usually chosen. Or you switch a cable between the two systems, then you have two antennas with a + set-up: a horizontal and a vertical Yagi. Of course, it would also be conceivable to lay two cables to use both systems at the same time, or to switch only in the shack.

If you only want to have a fixed, non-switchable circular polarisation, cables of different lengths are sufficient, which are brought together on one cable via a 3dB coupler (splitter).

If you want maximum flexibility, you can mount a remote polarisation switch (see accessories) on the antenna. From this box, two cables go to the antenna, one coaxial and one control cable to the radio. The remote switch then offers the option of switching between left- or right-hand circular polarisation or between horizontal or vertical linear polarisation.