If you look at the structure of a TV aerial, you’ll observe that it is made up of multiple rods. Are these rods of same length? No, they are not. It’s because the different lengths of the rods are used to determine the frequency they are going to pick up. There are different frequencies and signals of the TV channels present in the air. These are of different frequency bands like some channels ranges in the UHF band while others range in the VHF band. Thus, the signal that is received by the antenna is dependent on the structure of the antenna, the frequency available in the air as well as on the location of the air.
Where is the frequency signal of the UHF and VHF bands present?
These signals are present all around in the air at a height which is why the aerialsare placed at the roof or in the attic. Mostly, the outdoor antennas are able to catch these signals. Thus, the higher and better the direction of the antenna, the more the tv aerials will catch the signals and show the respective channel on the television.