Understanding SSB Frequency and Band Edges for Ham Radio Operators

Single Sideband (SSB) operation requires careful attention to the relationship between a radio's displayed frequency (suppressed carrier) and the actual 3 kHz wide audio signal. This resource clarifies how Upper Sideband (USB) and Lower Sideband (LSB) signals occupy spectrum above or below the indicated frequency, respectively. It provides practical examples for General Class operators on the 20m and 40m bands, such as setting a VFO to 14.226 MHz for USB on 20m or 7.178 MHz for LSB on 40m, to maintain a safe margin from band edges.

The resource emphasizes the critical importance of staying within allocated band limits to prevent out-of-band emissions, particularly when operating close to band edges. It includes relevant excerpts from FCC Regulation Part 97, specifically section 97.307, which details emission standards, necessary bandwidth, and spurious emission attenuation requirements. The text explains that unused sidebands are considered spurious emissions and notes that modern HF equipment typically exceeds the 43 dB spurious emission reduction standard, often achieving 60 dB or more.