Design Calculations for End-Fed Quarter-Wave Antenna

Date: 2026-01-12

• Compute wavelength: lambda(m) = 300 / f(MHz).
• Quarter-wave length L0 = lambda / 4.
• Apply velocity factor and end effect: L = L0 * VF * K.
• Typical K is 0.95 to 0.98 depending on diameter and height.
• Counterpoise length is often 0.05 to 0.25 lambda.
• Estimate feed impedance and choose a matching network if needed.