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8el 3.4mtr Boom

G0KSC SC14408L 8el 144Mhz Yagi Antenna with a 3.4 Metre Length Boom

updated July 2010

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 8 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 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.

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 and gain alone and you will never know what you are missing!!

 

SC14408L by M5TAW

 

Dimensions in Metres - all tubing 1/2 inch or 13mm diameter, mail for other sizes and tapered elements

Element spacing:

  • Ref =      0
  • Driven =  .360
  • D1 =       .495
  • D2 =       .877
  • D3 =      1.419
  • D4 =      1.993
  • D5 =      2.683
  • D6 =      3.418

Element sizes per element half:

  • Ref =       .5055
  • Driven =   .504
  • D1 =         .471
  • D2 =         .456
  • D3 =         .440
  • D4 =         .4325
  • D5 =         .422
  • D6 =         .3975

Performance figures @ 144.300Mhz:

  • Froward Gain: 12.80dBi free space
  • Front to Back: 26.83dB

Sky Temperature @ 144.100MHz = 247.5 Kelvin

G/T @ 144.100MHz = -11.17dB

 

 

Dimensions in Metres - all tubing 12mm diameter, mail for other sizes and tapered elements

Element spacing:

  • Ref =      0
  • Driven =  .360
  • D1 =       .495
  • D2 =       .877
  • D3 =      1.419
  • D4 =      1.993
  • D5 =      2.683
  • D6 =      3.418

Element sizes per element half:

  • Ref =       .5065
  • Driven =   .504
  • D1 =         .472
  • D2 =         .457
  • D3 =         .441
  • D4 =         .4335
  • D5 =         .423
  • D6 =         .3985

Performance figures @ 144.300Mhz:

  • Froward Gain: 12.78dBi free space
  • Front to Back: 26.76dB

 

Azimuth Plot


 


Elevation Plot

 

 

This fantastic antenna at 10m 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!

 
 
 
 

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