Question T3A12
From subelement T3 - T3A
What is the effect of fog and rain on signals in the 10 meter and 6 meter bands?
Why is this correct?
At HF frequencies like 10 and 6 meters, fog and rain have little effect on signal propagation. Unlike microwave frequencies where precipitation can absorb signals and decrease range, these lower frequencies pass through weather conditions with minimal attenuation. The water droplets in fog and rain are much smaller than the wavelengths of 10m and 6m signals, so they don't significantly interact with or absorb the radio waves.
Memory tip
Remember the frequency-absorption pattern: higher frequencies are more affected by weather. As you move up the spectrum from HF to VHF to UHF to microwave, precipitation becomes increasingly problematic. This creates a useful mental framework for predicting weather effects across different amateur bands.
Learn more
In practical operation, this frequency-dependent weather effect becomes important for emergency communications and contest planning. While microwave systems like 10 GHz and above require clear weather paths for reliable communication, HF through low VHF frequencies maintain their propagation characteristics during storms. This is why HF remains the backbone for emergency communications during severe weather events when higher frequency systems may fail due to precipitation attenuation.
Think about it
Why do you think emergency communication networks rely heavily on HF frequencies rather than microwave systems during severe weather events?