What could cause a broadcast AM or FM radio to unintentionally receive an amateur radio transmission?

• A. The receiver is tuned to the wrong frequency
• B. The receiver is unable to reject strong signals outside the band
• C. There is a short circuit in the receiver
• D. The antenna is misaligned

Answer: (B)

The option indicating that the receiver is unable to reject strong signals outside the band is correct because this situation can lead to unintentional reception of amateur radio transmissions. Most radio receivers have a feature called selectivity, which helps them to filter signals and reject interference from nearby frequencies. If a receiver is not designed with sufficient selectivity or if it is experiencing issues, it may pick up transmissions from amateur radio operators even when it is not tuned to their specific frequency.

In this context, strong signals—such as those from an amateur radio station operating near the broadcast frequencies—can overwhelm the receiver, allowing unwanted signals to bleed through and be heard even if the radio is ostensibly tuned to a broadcast station. This phenomenon often occurs in AM and FM receivers due to their inherent design limitations in filtering out signals that are not specifically targeted by the receiver’s tuning parameters.

Other factors, such as the receiver being tuned to the wrong frequency or having a short circuit, would not specifically cause the unwanted reception of amateur radio transmissions in the same manner. Misalignment of the antenna could lead to poor signal reception or quality issues, but it does not directly increase the likelihood of picking up signals from amateur bands if the receiver's selectivity is operating normally.