Ham Radio General Class Practice Test

What is the effect on an audio device or telephone system if there is interference from a nearby CW transmitter?

1. On-and-off humming or clicking

2. A CW signal at a nearly pure audio frequency

3. A chirpy CW signal

4. Severely distorted audio

The correct answer is: On-and-off humming or clicking

When a nearby continuous wave (CW) transmitter causes interference in an audio device or telephone system, the most common effect is typically characterized by an on-and-off humming or clicking sound. This happens because CW signals are transmitted as a series of dots and dashes, or keying, producing an intermittent signal. The audio device may interpret these rapid on-off transitions as audible clicks or hums, which humans can perceive as disruptive noise. In terms of the other possible outcomes, a CW signal at a nearly pure audio frequency wouldn't typically describe the effect of interference, as the CW signal itself is not meant to be converted cleanly to audio; rather, it interrupts the normal audio signal. Similarly, while a chirpy signal may occur under certain specific conditions, it doesn't accurately reflect the general effect on average audio devices. Finally, distorted audio could result from various issues but isn't the main characteristic caused by CW interference; rather, that might suggest problems with the audio electronics themselves or significant distortion due to signal overload.