What antenna length should be used to create a dipole antenna that emits 100-mhz electromagnetic waves, a frequency typical of fm radio broadcasts?

1.50 meters There are several different types of dipole antennas so I'm going to have to guess at which one you actually desire. If kind of makes sense that the type hasn't been specified since the actual full name of the dipole type gives away the length of the dipole. The types are Short dipole: The length is a lot smaller than half a wave length and this type of antenna is very inefficient. It's unlikely that you want this antenna since its efficiency is so low and the actual wave using it is pretty much irrelevant. Full-wave dipole: A nicely efficient dipole antenna who's total length is a full wave of the frequency being transmitted. But it has a rather high impedance which makes matching it to a transmitter harder for only a 2 dB gain in power. So this too is rather unlikely. Half-wave dipole. Another efficient antenna and this is the one most likely desired by this problem. It consists of two wires, each of which is 1/4 of the wavelength being transmitted and the total length of the antenna is half the wavelength being transmitted. So let's do the math. Calculate the wavelength by dividing the speed of light by the frequency. So 299792458 m/s / 100000000 1/s = 2.99792458 m So let's call the wavelength 3.00 meters. Since the total length of a Half-wave dipole is half a wavelength, the antenna length will be 3.00 m / 2 = 1.50 m So the antenna has a total length of 1.50 meters.