Both satellite and ground-based transmissions can use microwaves.
The world Administrative Radio Congress (WARC) is the organization within the International Telecommunications Union (ITU) that regulates the use of radio spectrum. WARC has designated two frequency bands for satellite communications (SATCOM):
- The C-band in the frequency range between 3.7 and 4.2 GHz, and from 5.9 to 6.4 GHz
- The Ku-band in the frequency range between 11 and 12 GHz.
Both types of communications require ground-based receivers to have a parabolic antenna to receive the signal. The antenna also has to be directed toward the satellite so that it focuses the parabola on the satellite transmission.
Terrestrial microwave transmissions also can only take place when there is a direct line of sight between the sender’s and receiver’s antenna. This is why you see microwave transmission towers which are covered with antennas pointing in every direction. These antennas need to point at different transmission towers.
The absorption of microwaves in the atmosphere is such that there is very little interference between different microwave towers.
Overall, the advantages of using microwave frequency transmissions are considerable. Because of their high frequencies, they are capable of broadcasting large quantities of information. Microwave communication systems, because of microwave repeaters, also have the ability to transmit data over extremely long distances.
When the repeater receives the signal of transmission, it undergoes a conversion into an electrical signal and retransmission as microwave signal at very full strength. Through the Earth’s atmosphere, microwave radio communication systems propagate signals.
Because of this direct line of site transmission, microwave radio systems transmit several data channels between certain points without a reliance on wire cables or fiber optics which are physical media.
Because there is no need for expensive attenuation equipment or physical cables, microwave technology is relatively cheap with low construction costs compared with other forms of data transmission such as wire-line technologies.
Want to learn more? Tonex offers Microwave and SATCOM Systems Principles and Practical Operation, a special 4-day hands-on training course that provides a complete background for understanding basic operation and setup of both terrestrial and satellite microwave systems.