Which of the following is a common issue when using a highly directional antenna?

A highly directional antenna is designed to focus energy in a specific direction, which enhances the signal strength in that chosen direction. This design effectiveness means that while you gain more signal in that focused lobe, you also experience a reduction in coverage area overall. This is because the antenna has less sensitivity to signals coming from other directions.

In contrast, antennas that radiate more broadly provide coverage to a wider area, but with less gain in any single direction. Consequently, while using a highly directional antenna can improve signal quality in the desired direction and possibly increase gain, the principle of directing the signal also inherently limits the area where the antenna can effectively communicate. This limited coverage can be particularly noticeable in situations where the other stations or signals fall outside the narrow beamwidth provided by the antenna.

This distinction is crucial for operators to understand, especially when the goal is to communicate with multiple stations or cover a larger geographical area.