Work out antenna length instantly with clear inputs, formula shown and shareable results.
Wavelength is the speed of light divided by frequency, and a resonant element is a simple fraction of it. Real conductors are slightly shorter than the free-space figure because of end effect and conductor diameter, which is what the velocity factor of about 0.95 accounts for.
Antenna length
lambda = c / f; element = lambda x fraction x velocity factor
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
End capacitance and the finite conductor thickness make it electrically longer than its physical length, so it must be trimmed by roughly 5%.
It concentrates radiation closer to the horizon, giving about 3 dB over a quarter wave, but needs a matching network because it is not resonant.