Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Wavelength (m)

Required number input.

Compute the effective length of a half-wave dipole as lambda divided by pi. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Effective length (m)

The resulting effective length returned as a number.

• Antenna formulas assume stated frequency, impedance match, polarization, efficiency, aperture, and propagation geometry. Nearby objects, ground, feed loss, multipath, regulatory averaging, near-field conditions, and pattern variation can make free-space or ideal-aperture results inaccurate.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Short Dipole Rrad

  Compute the radiation resistance of a short dipole from its length and wavelength using Rrad = 80 x pi^2 x (l/lambda)^2.

• Effective Aperture

  Compute the antenna effective aperture in square meters as Ae = lambda^2 x G / (4 x pi); wavelength and linear gain must be positive.

• Beamwidth Approx

  Approximate the parabolic dish half-power beamwidth in degrees as 70 x lambda / D; wavelength and dish diameter must be positive.