Ham Radio General Class Practice Test 2026 – Complete Exam Prep

The mode of transmission most affected by ionospheric conditions is single sideband (SSB). This is because SSB signals rely heavily on the ionosphere for long-distance propagation, especially in the high-frequency (HF) bands. The ionosphere can reflect these signals back to Earth, but its conditions can vary due to factors like solar activity, time of day, and geographical location, which in turn affects the coverage, strength, and clarity of SSB communications.

In contrast, frequency modulation (FM) and amplitude modulation (AM) signals are typically used in VHF and UHF bands where ionospheric effects are minimal due to the higher frequencies and shorter distances involved in typical operations. Continuous Wave (CW) transmission, while it can be affected by ionospheric conditions, is generally more resilient to variations due to its simple waveform, allowing for effective communication even under less-than-ideal circumstances. However, SSB specifically relies on the ionosphere for effective long-range communication, making it the most impacted mode.