If radio waves are invisible to the human eye, how can one measure wavelength?

Question

If radio waves are invisible to the human eye, how can one measure wavelength?

In: Physics

Answer 1

All radiation (visible light included) are measured indirectly with equip that turns the energy into electric signals. And all radio signals have a direct relationship between their frequency and wavelength. So if you know the frequency then you can calculate the wavelength. Then once you know the wavelength you can build an antenna to specifically receive that frequency/wavelength. The length of a radio antenna (think car) is specifically designed to receive a narrow range of frequencies/wavelengths.