Which of the following is a consequence of excessive voltage drop?

Excessive voltage drop in an electrical system can lead to poor performance of the transceiver. When voltage is reduced below the required operating levels, the device fails to perform optimally, which can manifest as lower audio quality, reduced transmission range, or even complete failure to transmit or receive signals. This is particularly relevant in amateur radio, where maintaining appropriate voltage levels is crucial for reliable communication.

While energy efficiency, antenna length, and output power are important parameters in electronic systems, they are not directly affected in the same manner by excessive voltage drop. Instead, reduced voltage primarily impacts the functioning of the transceiver itself, highlighting the importance of ensuring all components in the system are properly powered to avoid degradation in performance.