Radio frequencies are part of the electromagnetic spectrum.
Most people are familiar with AM and FM radios, but radios are just some of the wireless devices that use radio frequencies to operate. A lesser-known use of radio frequencies is as a visual tool in astronomy. Objects in outer space often emit large amounts of energy in addition to visible light, such as X-rays and radio waves.
Characteristics of radio frequency
1. Non-depletion
Radio spectrum resources are different from resources such as minerals and forests. They can be used by humans, but It will not be consumed. Not using it is a waste. Improper use is even more of a waste. It can even cause harm due to interference caused by improper use.
2. Reusability
Although radio spectrum is exclusive, radio frequencies can be reused and utilized under certain time, region, frequency domain and coding conditions. That is, different radio services and equipment can be frequency reused and used.
Reference for the above content: Baidu Encyclopedia-Radio Frequency