How can excessive SWR affect a radio system?

Excessive Standing Wave Ratio (SWR) indicates a mismatch between the transmitter and the load, such as an antenna. This mismatch can result in significant problems for the radio system. When SWR is high, not all of the power sent from the transmitter is effectively radiated by the antenna; some of it reflects back towards the transmitter. This reflected power can lead to a variety of issues.

First, the transmitter may experience signal loss because it's not transferring its full power to the antenna. This can result in reduced effectiveness of the transmission since less power is utilized for broadcasting the signal.

Additionally, the reflected power can cause the transmitter to overheat due to the energy not being radiated away; instead, it remains in the transmitter and can generate excess heat. If the overheating continues without mitigation, it can eventually lead to permanent damage to the transmitter's components. High SWR can trigger automatic protection circuits within the transmitter, causing it to shut down or reduce power output to prevent damage.

Therefore, the correct answer highlights the risks associated with excessive SWR, specifically focusing on signal loss, the potential for overheating, and the risk of damage to the transmitter.