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 commercial gain exists, express permission of G0KSC must be sought.

The new LFA Plus2 range includes an additional 2 reflectors which are used in order to maintain pattern stability throughout the 1MHz coverage (144-145MHz).

Currently these antennas are available in METRIC SIZES ONLY. Imperial will be launched at a later date.

As with ALL LFAs this antenna requires no matching, it has a 50 Ohm input impedance.

2 x 11el Plus2 LFA Yagis at OZ1CT (G0KSC 6m/4m dual bander on other side of the tower)

The VK3VG 2 x 11el Plus2 2M LFA Yagi

4nec2 (with nec4 engine) Elevation plot of the 11el Plus2 LFA Yagi

The 11el Plus2 Azimuth plot from the 4nec2 antenna modelling package

SWR as presented in the 4nec2 antenna modelling package using nec4.1 Double Precision calculation engine

How the antenna will look when built

PLEASE NOTE:

• This antenna WILL NOT show the true SWR in any antenna modelling package unless you are using one which uses the latest NEC4 calculation engine DO NOT confuse EZNEC with the NEC engine. EZNEC uses nec2 by default
• There are two sets of measurements listed below. One uses imperial sizes, the other uses metirc sizes. Ensure you use the correct one for the material you have
• 'within one or two millimetres' Will not do! take the time to ensure you get the spacing ant element lengths as close as you possibly can to the measurements below to ensure good, solid performance
• Please read the 'how to make the LFA Loop' page here
• Please do not alter segmentation or try to 'tune' the antenna unless you have nec4 or better. SWR will not read true within anything else

Performance European Version

Forward Gain:                                   15.26dBi at 144.300MHz

Front to Back Ratio:                           25.26dB at 144.300MHz

Peak Gain:                                       15.27dBi

Peak F/B:                                          25.74dB

Bandwidth:                                       144-145MHz below 1.1:1

Build Dimensions for European Version - mail me if you need 12 or 13mm tube driven loop sizing

Element                 Spacing (m) Half element Length (m)            Element Notes

Plus2 Rear Reflectors      0             .508                          above and below loop by 225mm 8mm tube

Reflector                        .192         .514                          8mm Diameter tube or solid rod

DE1                                .354        .444                         10mm Tube

DE2                                .519        .444                         10mm Tube (feedpoint)

D1                                  .750        .478                          8mm Diameter tube or solid rod

D2                                1.214        .461                          8mm Diameter tube or solid rod

D3                                1.625         .449                         8mm Diameter tube or solid rod

D4                                2.167         .453                         8mm Diameter tube or solid rod

D5                                2.896         .447                         8mm Diameter tube or solid rod

D6                                3.688         .441                         8mm Diameter tube or solid rod

D7                                4.526         .436                         8mm Diameter tube or solid rod

D8                                5.435         .424                         8mm Diameter tube or solid rod

D9                                6.226         .425                         8mm Diameter tube or solid rod

Notes:

DE1 and DE2 are joined at the ends by 8mm tube

Feed point is the centre of DE2

As always, any questions please ask!

Justin G0KSC