434 4 element yagi
If you would like to make your own 434Mhz yagi, here is some info to help you. It is up to you how many elements you use. I use RG-58 because of it’s VF and Impedance. The VF lets the balun be shorter. The image left does not have a balun. It is a functional design, but a balun could help some. Let me know if you have any questions.
Brian
Materials
- Aluminium arrows (22/64″ or 8.73125mm)
- 1 inch wide non-conductive material for the boom
- RG58 coax
- 50 ohm BNC connector or SMA-Male (whatever your radio uses)
- Balun – Here is a PDF with the info to create your own balun using RG-58 (Balun_for_434_MHz_using_228_mm_loop_of_RG-58)
- Tools for bending and soldering
Antenna Details
These antenna designs were calculated using VK5DJ’s Yagi Calculator
I like 3 elements for best performance for the size but also made a 4 element. For the boom, if you do not have a non-conductive material (like pvc conduit) you can build insulators (13mm or greater) to mount the elements to.
3 Elements
Frequency : 434 MHz
Wavelength : 691 mm
Rod Diameter : 8.73125 mm
Boom Diameter : 25 mm
Boom Length : 230 mm
Elements : 3
Gain : 6.9 dBd (approx.)
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Reflector Length : 334.4 mm
Reflector Position : 0 mm
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Dipole Length : 320.2 mm end to end
Dipole Position : 138 mm from reflector
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Director #1 Length : 289.9 mm
Director #1 Position : 51.8 mm from Dipole
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Directors / Parasitics are isolated.
Please choose an isolater thicker than : 13 mm
Positions are center to center measurements.
4 Elements
Frequency : 434 MHz
Wavelength : 691 mm
Rod Diameter : 8.73125 mm
Boom Diameter : 25 mm
Boom Length : 345 mm
Elements : 4
Gain : 8.6 dBd (approx.)
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Reflector Length : 334.4 mm
Reflector Position : 0 mm
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Dipole Length : 320.2 mm end to end
Dipole Position : 138 mm from reflector
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Director #1 Length : 289.9 mm
Director #1 Position : 51.8 mm from Dipole
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Director #2 Length : 286.1 mm
Director #2 Position : 124.3 mm from Director #1
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Directors / Parasitics are isolated.
Please choose an isolater thicker than : 13 mm
Positions are center to center measurements.