intersting

Any material, whose temperature is above absolute zero, does radiate em waves In practice, we term the frequencies above 20KHz as radio frequency.The fields radiated can be coupled with the help of suitable antenna at a distance. This distance depends on the transmitter power level and the frequency.

Waves in the HF range (3 - 30 MHz) travel as sky wave at a distance. VHF, UHF, SHF ranges are LOS ranges. Generally, the geographical area covered by a transmitter is termed as its range. Within this area, the correctly tuned receiver will be able to extract the modulating signal and there should not be any error in detection unless there is bursts of noise.

This area can be called an RF environment.

When we are using Bluetooth mouse for our desk-top PC in our home, we are giving an example of RF environment in our room or home.