Ham Radio General Class Practice Test

How close to the lower edge of the 40 meter General Class phone segment should your displayed carrier frequency be when using 3 kHz wide LSB?

1. 3 kHz above the edge of the segment

2. 3 kHz below the edge of the segment

3. Your displayed carrier frequency may be set at the edge of the segment

4. Center your signal on the edge of the segment

The correct answer is: 3 kHz above the edge of the segment

When using a 3 kHz wide Lower Sideband (LSB) mode on the 40-meter band, it's important to ensure that the displayed carrier frequency is properly positioned within the allocated segment to avoid interference with adjacent frequencies and comply with regulations. The correct answer indicates that your displayed carrier frequency should be set 3 kHz above the lower edge of the General Class phone segment. This positioning ensures that the edge of your modulated signal, which extends 3 kHz below the displayed carrier frequency due to the nature of LSB operation, will not encroach upon frequencies below the legal limit of the segment. Thus, if your carrier is set 3 kHz above the lower edge, the lowest frequency of your transmission would start right at the edge of the allocated segment, allowing for optimal utilization of the band while adhering to the required regulations. Setting the frequency this way also helps prevent overlap with other operators who might be using nearby frequencies. In contrast, positioning your carrier frequency lower or directly at the edge could result in unintentional interference with other ongoing transmissions or violate spectrum usage rules. This principle of maintaining a clear and interference-free operation is fundamental in amateur radio practices.