Antenna Information

Antennas come in a wide range of shapes and sizes. There are two core aspects to consider when selecting an antenna.

Frequency
Every radio transmits and receives on a frequency. An antenna is much like a car’s exhaust system; it needs to be tuned to the frequency to achieve maximum efficiency. If you use an antenna that is not tuned or whose frequency does not match the radio’s frequency, efficiency can be severely impacted.

Gain or Amplification
The gain of an antenna is the ratio of the signal entering the antenna to the signal exiting it. This calculation can be quite complex and is typically measured in decibels (dB). As a basic rule of thumb, every 3dB of gain doubles the input power.

Example:
Radio Power = 10Watts
Antenna Gain = 7dB (7/3=2.333 Amplification)

10watts x 2.333 Amplification = 23.3 Watts of effective power

This can cause licensing issues, as licenses are based on radiated power rather than the radio’s power.

Antenna Earthing
On most antennas, a good earth connection is essential for good communication. The best way to think about the Earth is when transmitting, the radio uses the Earth to “push” against. So, if you don’t have a good earth, the radio’s coverage can be severely impacted.