Why does a 1/4 wavelength antenna have to be 1/4 wavelength? What property of the wave is responsible for this restriction? I've been trying to understand how a 1/4 wavelength antenna works and the best explanation, relatively speaking, was on the following website, http://www.sm0vpo.com/antennas/anten.htm [Broken]. It still doesn't make any sense. Maybe if I could understand how a 1/4 wavelength antenna works, I could figure out why there is a restriction on the length.