What is the relationship between the gain of a CB Antenna and its signal coverage?

The relationship between the gain of a CB Antenna (i.e., a citizen band antenna) and its signal coverage can be summarized as follows: Antenna gain directly affects the signal coverage, but it is not the only determining factor. The following is a specific analysis and explanation:
Definition of antenna gain: Antenna gain describes the intensity of antenna radiation in any direction in free space. The unit of gain is decibel, expressed as dBi, where "i" represents isotropic, that is, the ratio of the signal strength emitted by any antenna to that of an isotropic antenna. An isotropic antenna is a theoretical antenna with the same signal strength in all directions.
Relationship between gain and signal coverage:
The greater the gain, the wider the coverage: Generally speaking, the greater the antenna gain, the stronger the signal strength it radiates, so theoretically it can cover a longer distance. For example, high-gain antennas are more effective for medium and long distances, and their ability to penetrate walls will also be improved, thereby extending the effective coverage of wireless network signals.
But it is not the case that the greater the gain, the better: although the increase in gain can improve the coverage range, the greater the gain, the smaller the antenna angle, that is, the more concentrated the radiation direction of the antenna, which may to poor signal coverage in some directions. Therefore, when selecting an antenna, it is necessary to weigh the actual needs and environmental conditions.
Other influencing factors: In addition to antenna gain, signal coverage is also affected by many factors, such as transmission power, receiving sensitivity, propagation environment (such as terrain, buildings, weather, etc.) and frequency.
The correspondence between specific gain and coverage: Antennas with different gains have different coverage in different environments. For example, in indoor environments, an antenna gain of 2-7dbi may be more suitable; while in outdoor environments, a higher gain may be required to cover a longer distance. However, the specific coverage range still needs to be tested and evaluated according to actual conditions.
In summary, there is a close relationship between the gain of the CB Antenna and its signal coverage, but it is not a simple linear relationship. When selecting and using an antenna, it is necessary to make comprehensive considerations and weigh them according to actual needs and environmental conditions.