Omnidirectional Antenna Beamwidth Analysis

A service of Green Bay Professional Packet Radio ®


Enter the antenna's 3 dB vertical beamwidth (<120°) degrees
Enter the antenna's downtilt angle (<90°) degrees
Enter the effective Earth radius (K factor)
Enter the antenna's height (AGL)

AGL  Above Ground Level.  Height above common ground to the the mid-point of the radiating antenna.

The K factor accounts for refraction of radio waves close to the surface of the earth.  For antenna towers less than a couple of thousand feet above the surface, a K factor of 1.33 is usually adequate for most line-of-sight calculations over average terrain.

Typical Values of K
                                        Summer  Winter

Dry mountains (above 1500 meters)       1.20    1.20
Mountains (to 1500 meters)              1.25    1.25
Midwest and Northeast                   1.50    1.30
South and West Coast                    1.55    1.35
Southern Coast                          1.60    1.50