Ham Radio General Class Practice Test

What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?

1. 14.347 to 14.647 MHz

2. 14.347 to 14.350 MHz

3. 14.344 to 14.347 MHz

4. 14.3455 to 14.3485 MHz

The correct answer is: 14.347 to 14.350 MHz

To determine the frequency range occupied by a 3 kHz Upper Sideband (USB) signal with a carrier frequency of 14.347 MHz, you need to analyze how USB modulation works. In USB, the information is transmitted as frequencies above the carrier frequency. When the displayed carrier frequency is set at 14.347 MHz, the upper sideband will extend from the carrier frequency up to 3 kHz above it. Therefore, the uppermost frequency of the signal can be calculated by adding the bandwidth of the signal (3 kHz) to the carrier frequency. Thus, the highest frequency will be: 14.347 MHz + 0.003 MHz = 14.350 MHz. Consequently, the bandwidth extends from the carrier frequency down to the frequency 3 kHz below the carrier. The lower frequency bound would naturally be: 14.347 MHz - 0.003 MHz = 14.344 MHz. Therefore, the frequency range occupied by this USB signal is from 14.344 MHz to 14.350 MHz. The answer provided fits within that range, indicating its validity and accuracy. This reasoning illustrates how USB signals occupy a frequency range above their carrier frequency in a defined bandwidth, showing the importance of understanding