The most common construction method uses copper plumbing pipe due to its high conductivity and ease of soldering.
To build an effective J-pole, dimensions must be precise based on your target frequency. The standard formula uses the speed of light adjusted for the velocity factor of the material (typically copper pipe or 300-ohm twin-lead). Standard Formulas (in inches) 8856 / Frequency (MHz) Radiator Length: 5540 / Frequency (MHz) Stub Length: 2770 / Frequency (MHz) Spacing: ~2 inches for VHF; ~1 inch for UHF 2-Meter Band Example (146 MHz) Overall Length: 60.6 inches Radiator: 37.9 inches Stub: 19.0 inches Construction Steps j-pole antenna design pdf
The following design parameters must be calculated to design a J-pole antenna: The most common construction method uses copper plumbing
Cut one piece of copper pipe to the (approx. 98 cm). Cut a second piece of copper pipe to the Matching Section Length (approx. 49 cm). Standard Formulas (in inches) 8856 / Frequency (MHz)
Mount the antenna to a mast or support and adjust the spacing and configuration as needed.
Use a pipe cutter for clean edges. You will need one long piece (radiator + stub base), one short piece (stub), and a cross-piece.