The higher the antenna above the ground, and free from obstruction, the longer your communication range.

To calculate the line of sight comnunication range, and height of your transmitting antenna by using these formulas:

OR

In the Metric System

To calculate the line of sight comnunication range, and height of the transmitting antenna, and the height of the receiving antenna by using these formulas:

OR

In the Metric System

For Example:

  If you are standing on your balcony at you high rise apartment at 28 floors above the ground or 336 feet above the ground with your walkie-talkie, your line of sight talking range would be 25.9 miles.

6.47 miles = square root (2 x 5.5 feet) + square root (2 x 5 feet)

  25.9 miles = square root (2 x 336 feet)

                !Warning!
   Make sure you have the CB antenna height don't exceed 60 feet above the ground from the top of the antenna to ground, or if the antenna height would exceed 60 feet above the ground while mounted on the roof of a building structure, the maximum antenna height is 20 feet above the building's roof. Local laws and community deed restriction may limit the height less than the FCC rules and regulations, or prohibit of the mounting of any CB antennas on the on the property.