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

A.
Minimum output power level of 2 W

B.
Accurate Earth Bulge calculations

C.
Grid antennas at each endpoint

D.
A minimum antenna gain of 11 dBi at both endpoints

E.
A Fresnel Zone that is at least 60% clear of obstructions