Canvey Island, Essex, England Justin@g0ksc.co.uk
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: 1 - 2 minutes
G0KSC SC2804S 4el 28Mhz Yagi Antenna with a 3.7 Metre Length Boom

This is a good wide band Yagi for 28 to 29Mhz with a real flat SWR curve and good F/B. It has a short length boom of 3.7 mtrs and therefore can be made from a single piece 1inch square tube section. No boom support will be required.

Dimensions in Metres

Element spacing:

  • Ref =      0
  • Driven = 1.287
  • D1 =      1.776
  • D2 =     3.7

Element sizes per element half:

  • Ref =       2.649
  • Driven =  2.573
  • D1 =       2.443
  • D2 =      2.33

Performance figures @ 28.400Mhz:

  • Froward Gain: 8.29dBi free space
  • Front to Back: 21.42dB
  • Radiation angle at 10 Metres above ground: 14 degrees

Element diameter:

Each element is made out of single piece 1/2 inch (12.7mm) aluminum tubing Each element half length needs to be doubled in order to gain your total element size. No difference is length needs to be calculated for the 1, 3/4inch or 2inch boom as the elements sit high enough above the boom for the boom to have no influence.

If you are only able to obtain 1/2 inch elements in 6 metre lengths and can only obtain 5 metre lengths, join them in the middle at the insulator with a small piece of 3/8 inch tubing (600mm long) bolt the element to the insulator with 2 bolts either side of the boom.

NOTE:

You can build this antenna with 13mm diameter tubing using the same parameters above. Slightly higher front to back ratio and forward gain will be seen along with a narrower SWR curve.

For construction information see 'G0KSC insulators' and the UKSMG article from the main menu on the home page. 

Read Time: 1 - 2 minutes
G0KSC SC0404S 4el 70Mhz Yagi Antenna with a 1.457 Metre Length Boom

This is my smallest 70 Mhz beam. It has a short length boom which is made from a single piece 1inch square tube section. No boom support will be required.

This antenna shows good performance particularly when stacked. Take a look at the last plot on this page which shows the pattern 7 metres above ground with 2 beams, one stack 2.1 metres above the other.

Dimensions in Metres

Element spacing:

  • Ref =      0
  • Driven =  .409
  • D1 =      .600
  • D2 =     1.457

Element sizes per element half:

  • Ref =       1.053
  • Driven =   1.015
  • D1 =       .981
  • D2 =      .943

Performance figures @ 70.200Mhz:

  • Froward Gain: 8.84dBi free space
  • Front to Back: 17.33dB
  • Radiation angle at 10 Metres above ground: 10 degrees (5 degress for 2 stack)

Element diameter:

Each element is made out of single piece 1/2 inch (12.7mm) aluminium tubing Each element half length needs to be doubled in order to gain your total element size. No difference is length needs to be calculated for the 1inch or 1,1/4 inch boom as the elements sit high enough above the boom for the boom to have no influence.

NOTE:

You can build this antenna with 13mm diameter tubing using the same parameters above. Slightly higher front to back ratio and forward gain will be seen along with a narrower SWR curve.

For construction information see 'G0KSC insulators' and the UKSMG article from the main menu on the home page.