Antennas are a vital element of modern telecommunications, but how do they work and what do you need to know about them?
What is an antenna?
According to Explain That Stuff!, an antenna, or aerial, is a metal rod or dish that catches radio waves and turns them into electrical signals. These signals are then fed into a radio, television or telephone system.
Types of antennas
There are various types of antennas. The simplest type is a radio antenna, in the form of a long, straight, metal rod.
Antennas used for televisions vary widely, and those placed outdoors generally work better than those used inside. Many television antennas take the form of a dipole. The basic form of a dipole consists of a metal rod split into two pieces and folded horizontally. More complex dipole antennas have a number of dipoles fixed along a central rod. Antennas may also consist of circular loops of wire or take the form of a satellite dish.
Antennas can have different patterns of dipoles to allow for optimum concentration of the signal from a transmitter. Extra, unconnected dipoles are sometimes added to an antenna which bounce the signal to the receiving dipole, thus giving an added boost to the signal strength.
Different antennas pick up signals from various angles. A basic dipole picks up signals from in front of or behind its poles, but not from each end, while an antenna with a reflector, has one side that’s better for picking up signals than another. Another type of antenna, called a Yagi, also relies on picking up signals on a single side.
Understanding how different antennas work with regards to picking up signals is important when installing a TV aerial, so make use of expert services, such as Gloucester TV aerial installation specialists, Steve Unett Aerials (steveunettaerials.co.uk), to get the best quality signal possible.
Antennas also share a number of features that impact the functioning of the aerial. The directionality of an antenna relates to the direction in which an antenna picks up incoming radio waves. The gain of an antenna relates to how much it boosts the signal. Gain is measured in decibels and, the larger the gain, the higher quality the signal will be. Bandwidth relates to the range of frequencies or wavelengths over which the antenna works.