Inverted-V Calc | RF Field Tool

Inverted-V

EMCOMM Field Designer

Frequency (MHz)

Apex Angle (Degrees)

19.72 m Total Wire Length

9.86 m

Per Leg

~50 Ω

Est. Impedance

Lowering the apex angle reduces impedance. At 90°, you get a near-perfect 50Ω match for coax.

The Inverted-V Difference When you fold a dipole into a "V" shape, the resonant frequency actually drops slightly due to increased capacitance between the ends and the ground. To compensate, an Inverted-V usually needs to be 1% to 3% shorter than a standard flat dipole.

Key Formulae:

Impedance Tuning: A flat dipole has an impedance of 73 Ω. By dropping the ends to form an Inverted-V, you lower the impedance. At an angle of roughly 90∘ to 100∘, the impedance hits 50 Ω, which is a perfect match for standard RG-58 or RG-213 coaxial cable.

Height Matters: The apex should be as high as possible. If the apex is lower than λ/4 (quarter-wavelength), your ground losses will increase and your radiation angle will shoot straight up (good for NVIS, bad for DX).

End Clearance: Ensure the ends of the "V" are at least 2-3 meters above the ground for safety (to prevent RF burns) and to keep the tuning stable.