The range of a transmitter operating in the VHF and upper bands depends on the transmitter and receiver antenna´s height, and also the earth´s diameter. The next formulas can be used for ranges up to some hundreds kilometers.
Formula 1
Where:
S is the range in kilometers (km)
H is the transmitter´s antenna height in meters (m)
h is the receiver´s antenna height in meters (m)
Application Example:
What is the range of a VHF TV transmitter having an antenna height of 100 meters and received by an antenna placed 9 meters above the ground level?
Data:
H = 100 meters
h = 9 meters
S = ?
Applying formula 1:
