ARRL Technician Practice Exam

What might happen if the antennas on both ends of a VHF/UHF link are polarized differently?

1. Signal quality will improve

2. Signals could be significantly weaker

3. Communication will be faster

4. There will be no effect

The correct answer is: Signals could be significantly weaker

When antennas on both ends of a VHF/UHF link are polarized differently, the resulting signal can indeed be significantly weaker. This phenomenon is due to the principles of polarization, which refers to the orientation of the electric field of the radio wave. For effective communication, the antennas should ideally be aligned in the same polarization, whether that’s vertical or horizontal. When one antenna is vertically polarized and the other is horizontally polarized, the reception of the signal is not optimal. The mismatch leads to a loss of signal strength because only a fraction of the emitted energy from one antenna can be received by the other. This reduction in signal strength can ultimately affect the quality of the communication being attempted. In contrast, if the antennas matched in polarization, the signal transmission would be more efficient, resulting in stronger and clearer communication. Therefore, the right answer points to the fact that different polarizations between antennas can lead to a notable decrease in signal quality.