Question

One sometimes sees rows of evenly spaced radio antenna towers. A student remarked that these act like diffraction gratings. What did she mean? Why would one want them to act as a diffraction grating?

Short answer

Equally spaced antennas increase the resolving power of the setup by behaving like a diffraction grating.

Step-by-step solution

Given Data

A set of a large number of parallel slits of equal width and which are equidistant between the centers is known as grating.

Diffraction gratings are used in the laboratory to disperse light into its component wavelengths. It has many slits, which produces a very sharp maxima due to which angle of deviation can be measured precisely.

Series of antenna towers

Equally spaced antennas increase the resolving power, that is given by

R = Nm

Where, R is resolving power, N is Number of antennas, and m is an integer other than 0.

Greater resolving power means better quality of signal that is being transmitted along with elimination of unnecessary noise. Thus, by behaving like a diffraction grating, equally spaced antennas increase the resolving power of the setup.