What is always required to establish a high quality 2.4 GHz RF link at a distance of 3 miles (5 kilometers)?

What is always required to establish a high quality 2.4 GHz RF link at a distance of 3 miles (5

kilometers) is a Fresnel Zone that is at least 60% clear of obstructions. The Fresnel Zone is an

elliptical-shaped area around the line-of-sight path between two antennas that reflects and refracts

the RF waves. The Fresnel Zone radius depends on the frequency of the RF signal and the distance

between the antennas. For optimal performance, the Fresnel Zone should be at least 60% clear of

any obstructions that may cause interference, attenuation, or multipath fading. The minimum output

power level, antenna gain, and antenna type may vary depending on the environmental conditions

and regulatory constraints, but they are not always required for a high quality RF

link. Reference: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-

109], page 75; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-

109], page 65.