G0KSC SC0412L 12el 70Mhz Yagi

Gain: 15.89 dBi
F/B: 29.43 dB
Elements: 12

Specifications

Performance

Gain: 15.89 dBi
Front-to-back: 29.43 dB
Elements: 12

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
D2	1735 mm	parsed from legacy body — confirm position vs length
D3	2677 mm	parsed from legacy body — confirm position vs length
D4	3928 mm	parsed from legacy body — confirm position vs length
D5	5680 mm	parsed from legacy body — confirm position vs length
D6	7384 mm	parsed from legacy body — confirm position vs length
D7	9253 mm	parsed from legacy body — confirm position vs length
D8	10996 mm	parsed from legacy body — confirm position vs length
D9	12903 mm	parsed from legacy body — confirm position vs length
D10	14258 mm	parsed from legacy body — confirm position vs length
Ref	1470 mm	parsed from legacy body — confirm position vs length
Driven	1024 mm	parsed from legacy body — confirm position vs length

About this design

G0KSC SC04012L 12el 70Mhz OWA Yagi Antenna with a 14.26 Metre Length Boom

This is a nice DX bean for 70Mhz. As always it has a nice flat SWR curve and is built with in a non-critical format so any small errors you make whilst constructing will not have a huge impact on performance.

I recommend this to be built from a 5 metre length of 1.75 inch box section aluminum with a 1.5 inch 5 metre length cut in to and slotted into each end. This will need additional support

Dimensions in Metres

Element spacing:

Ref = 0
Driven = .654
D1 = .982
D2 = 1.735
D3 = 2.677
D4 = 3.928
D5 = 5.68
D6 = 7.384
D7 = 9.253
D8 = 10.996
D9 = 12.903
D10= 14.258

Element sizes per element half:

Ref = 1.47
Driven = 1.024
D1 = .976
D2 = .951
D3 = .942
D4 = .929
D5 = .915
D6 = .909
D7 = .899
D8 = .903
D9 = .911
D10= .917

Performance figures @ 70.250Mhz:

Froward Gain: 15.89dBi free space
Front to Back: 29.43dB
Radiation angle at 10 Metres above ground: 10 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 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.