ARRL Technician Practice Exam 2026 – 400 Free Practice Questions to Pass the Exam

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.