OWA Yagis

G0KSC SC2806M 6el 28Mhz Yagi

Gain: 11.11 dBi
F/B: 21.03 dB
Elements: 6

Specifications

Performance

Frequency: 28–29 MHz
Gain: 11.11 dBi
Front-to-back: 21.03 dB
Elements: 6

Dimensions

Element dimensions

Element dimensions (parsed from legacy body — check before publishing)

Element	Position	Note
Ref	0 mm	parsed from legacy body — confirm position vs length
Driven	1244 mm	parsed from legacy body — confirm position vs length
D1	1727 mm	parsed from legacy body — confirm position vs length
D2	3779 mm	parsed from legacy body — confirm position vs length
D3	6683 mm	parsed from legacy body — confirm position vs length
D4	9311 mm	parsed from legacy body — confirm position vs length
Ref	2654 mm	parsed from legacy body — confirm position vs length
Driven	2583 mm	parsed from legacy body — confirm position vs length
D1	2458 mm	parsed from legacy body — confirm position vs length
D2	2408 mm	parsed from legacy body — confirm position vs length
D3	2402 mm	parsed from legacy body — confirm position vs length
D4	2311 mm	parsed from legacy body — confirm position vs length

Modelled performance

Plots

About this design

G0KSC SC2806M 6el 28Mhz Yagi Antenna with a 9.3 Metre Length Boom

This antenna has been designed for someone who loves 28mhz and who has a bit of space too! Working the WHOLE BAND from 28Mhz to 29Mhz, not just the CW or SSB portion. With great gain and front to back ratio to boot. Power limitations are whatever the limit of your coax is so if you have good coax, 3KW+ is not a problem.

Mechanical Construction

This Yagi has been designed to be built on a boom of 3 sections. The centre section should be a 5 metre length of 2 inch aluminum tubing whilst the out 2 sections should be 1, 3/4 inch tubing slotted in to the 2 inch section by around 600mm each end. Boom guying should not be required on this antenna.

If G0KSC insulators are to be used, these should be engineered to be 300mm long rather than 100mm and the width of each also should be doubled.

Small errors in your measurements or calculations when building this antenna WILL NOT greatly affect performance due to it's non-critical design.

Dimensions in Metres

Element spacing:

Ref = 0
Driven = 1.244
D1 = 1.727
D2 = 3.779
D3 = 6.683
D4 = 9.311

Element sizes per element half:

Ref = 2.654
Driven = 2.583
D1 = 2.458
D2 = 2.408
D3 = 2.402
D4 = 2.311

Performance figures @ 28.500Mhz:

Froward Gain: 11.11dBi free space
Front to Back: 21.03dB
Radiation angle at 10 Metres above ground: 15 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 2inch or 3 inch 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.