ARRL Technician Practice Exam

Which of the following may contribute to radio frequency interference?

1. Electronic devices using non-shielded cables

2. Improperly grounded equipment

3. All of these choices are correct

4. Signal distortion from other transmissions

The correct answer is: All of these choices are correct

Radio frequency interference (RFI) can arise from various sources, and the correct answer acknowledges that all the given choices can contribute to this issue. Electronic devices using non-shielded cables can pick up and emit unwanted electromagnetic signals, which may create interference in nearby radio communications. These cables can act like antennas, either radiating signals into the air or capturing them from it, leading to RFI. Improperly grounded equipment can also be a significant source of interference. Grounding helps stabilize voltage levels and shields against adverse electrical effects. When equipment is improperly grounded, it may generate noise or allow unwanted signals to mix with the intended transmission. Signal distortion from other transmissions is another aspect that leads to RFI. When signals from nearby transmitters interfere with the desired signal, it can result in degraded audio or data quality, which can be perceived as interference. Since all of these factors can indeed contribute to radio frequency interference, the selection reflecting that all choices are correct is accurate. Understanding how these various sources can lead to interference can help in both troubleshooting and preventing RFI in radio communication systems.