The main disadvantage of microwave transmission is that microwave towers can exchange data only if they have a clear line of sight between them with no obstacles such as buildings, hills or trees in the way. Other disadvantages include signal absorption by the atmosphere, weather interference and expense.
Microwave signals usually travel in a straight line from a transmitter to a receiver. If the signals pass through regions of air with different densities, as they might when crossing a body of water, the signals bend slightly. Instead of reaching the receiver, some signals are absorbed into the atmosphere, and the lost signals affect transmission quality. Microwave signals can also be affected by heavy rain, hail and snow. Raindrops and hailstones in particular are about the same size as the wavelengths of a high-frequency microwave. A storm can block microwave communication, creating a problem called rain fade. Another disadvantage of microwave transmission is the cost of the towers, which are expensive to build.
An advantage of microwave transmission is that rather than using cables or other physical wires, it uses electromagnetic waves with small wavelengths. The size of the wavelengths allows a transmitter to direct microwaves to a receiver in a narrow beam, improving efficiency. Furthermore, the high frequency of microwaves means that a microwave beam has a very large information-carrying capacity.