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.

Dish diameter (m)

Required number input.

Aperture efficiency

Optional number input.

Wavelength (m)

Required number input.

Compute parabolic dish gain in dBi as 10 x log10(eta x (pi x D / lambda)^2); eta defaults to 0.55. 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]

Parabolic gain (dBi)

The resulting parabolic gain 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.

• Gain From Aperture

  Compute the linear antenna gain as G = 4 x pi x A x eta / lambda^2 with aperture efficiency eta between zero and one, defaulting to 0.55.

• Beamwidth Approx

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

• Directivity From Gain

  Recover antenna directivity as directivityDbi = gainDbi - 10 * log10(efficiencyFraction), with efficiency defaulting to 0.6.