G0KSC SC0404S 4el 70mhz Yagi
- Gain
- 8.84 dBi
- F/B
- 17.33 dB
- Elements
- 4
Performance
- Gain
- 8.84 dBi
- Front-to-back
- 17.33 dB
- Elements
- 4
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 | 1457 mm | parsed from legacy body — confirm position vs length |
| Ref | 1053 mm | parsed from legacy body — confirm position vs length |
| Driven | 1015 mm | parsed from legacy body — confirm position vs length |
Plots
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.
