If power and wavelength are equal, which antennas would have the shortest range?

The choice of omni-directional antennas as having the shortest range when power and wavelength are equal is based on their inherent design and radiation pattern. Omni-directional antennas are designed to radiate and receive signals uniformly in all horizontal directions, which can lead to a more dispersed signal. This means that while they can cover a wide area, they do not concentrate the signal's energy in any specific direction.

As a result, the effective range can be limited compared to other types of antennas that focus their energy more effectively. Directional antennas, for example, are designed to send and receive signals in a specific direction, which enhances their range significantly. Similarly, dipole and loop antennas can also be configured to improve their directivity and gain.

In essence, the even distribution of energy from omni-directional antennas can lead to lower signal strength at greater distances, resulting in a shorter operational range when compared to antennas that concentrate their power in a specific direction.