Ham Radio General Class Practice Test 2025 – Complete Exam Prep

When charged particles from solar coronal holes reach the Earth, they can negatively impact High Frequency (HF) radio communications. These particles can create disturbances in the Earth's ionosphere, which is crucial for HF signals as they rely on ionospheric reflection to propagate over long distances.

During events such as solar flares and coronal holes, increased ionization can lead to a more active and turbulent ionosphere. As a result, HF communications may experience increased signal fading, distortion, and even complete loss of communication. This is why the correct answer reflects that HF communications are disturbed due to the presence of solar charged particles affecting the ionospheric conditions.

In contrast, VHF (Very High Frequency) and UHF (Ultra High Frequency) communications tend to be less impacted by these solar activities, and while ducting might occur under certain conditions, it is less directly influenced by the charged particles compared to HF communications.