Canvey Island, Essex, England
Twin boom quad
144MHz LFA Yagis
144MHz LFA Yagis

Low Noise LFA Yagis designed by G0KSC free to build for personal use.

144MHz LFA Yagis
70cms LFA Yagis
70cms LFA Yagis
Twin-Boom G0KSC Quads
G0KSC Twin-Boom Quads
Twin-Boom G0KSC Quads
G0KSC Custom Dish feeds - Above installation @ HB9Q
Custom low-noise dish feeds
Custom low-noise dish feeds
G0KSC Custom Dish Feeds

Above installation @ HB9Q

G0KSC Custom Dish feeds - Above installation @ HB9Q
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Read Time: 2 - 4 minutes
G0KSC SC14413m 13el 144Mhz Yagi Antenna with a 7.5 Metre Length Boom

Premium commercial versions of this antenna at Innovantennas

Please read the whole page, If you do not see the diameter tubing you need to have this antenna designed in or require tapered elements, Email me!

This antenna has been redesigned and represents what I beleive to the the 'ideal boom length' for an OWA direct feed 50 Ohm Yagi with 13 elements on 144MHz. This can be seen in the model in the super flat SWR, the high levels of F/B ratio along with the excellent gain and very low-noise pattern.

The model below is designed with 12.7mm / 1/2 inch dipole and 8mm - 5/16 inch elements. If you require a version of this antenna with another diameter wire, Email me and I will remodel. It is NOT POSSIBLE to simply resize the elements when using a VERY different diameter wire and get the best performance possible, Spacing and element diameters MUST be re-optimised to reproduce the best antenna possible.

REMEMBER, Gain does not make the best antenna on 2m. F/B, SWR Banwdith, Pattern Stability, Side Lobe suppression, Sky Teperature and G/T all play a role. Choose an antenna based on gain alone and you will never know what you are missing (mainly weak signals) !!

This Antenna has been designed in order to provide amazing stability in all weathers; Rain, Ice and Snow. Little effect will be seen from close-by objects (including other antennas) and impedance is contstant. Losses are at an absolute minimum with this antenna ensuring long-term, trouble-free, any-time operating and usage.

Dimensions in Metres - all tubing 1/2 inch / 13mm diameter dipole and 8mm / 5/16 inch parasitic elements, mail for other sizes and tapered elements

Element spacing:

  • Ref =      0
  • Driven =  .279
  • D1 =       .393
  • D2 =       .795
  • D3 =      1.401
  • D4 =      2.100
  • D5 =      2.861
  • D6 =      3.664
  • D7 =      4.482
  • D8 =      5.270
  • D9 =      6.054
  • D10 =    6.827
  • D11 =    7.493

Element sizes per element half:

  • Ref =       .5105
  • Driven =   .505 (.504 for 12mm dipole)
  • D1 =         .4785
  • D2 =         .4705
  • D3 =         .4605
  • D4 =         .453
  • D5 =         .4465
  • D6 =         .440
  • D7 =         .4345
  • D8 =         .4265
  • D9 =         .4195
  • D10 =      .4155
  • D11 =       .4135

Note: ALL elements 8mm (5/16inch) dipole is 1/2 inch with 12mm dipole figures in brackets.


Performance figures @ 144.300Mhz:

  • Froward Gain: 15.75dBi free space
  • Front to Back: 25.10dB
  • SWR Bandwidth - 1.5MHz below 1.1:1

Sky Temperature @ 144.100MHz = 225.1 Kelvin

G/T @ 144.100MHz = -7.77dB


Stacking information:

Vertical Stacking - 3.45M

Horizontal Stacking - 3.65M

Sky Temperature (4 antennas) @ 144.100MHz = 219.7 Kelvin

G/T @ 144.100MHz = -1.87dB

4 x Gain - 21.55dBi


Azimuth Plot

Elevation Plot

This fantastic antenna at 12m up

An Excellent SWR to go with the fantastic pattern!

Remeber, mail me if you have different diameter tube requirements and send photos of built antenna!