70-90 (SSN=10-35) Poor to fair conditions all bands up through 20 meters
<1.0e+01 Normal No impacts on HF.
A1-B9 No/Small Flare No or very minor impact to HF signals.
1.0e+00 Normal No impacts on HF.
K=0-2 (nT=0-20) [Aur=<3] Normal No impacts on HF. Noise S0-S2.
64-70 (SSN=0-10) Bands above 40 meters unusable
<1.0e+00 Normal No impacts on HF.
Even though the Electron Belt is farthest out in space, Electron Flux
has a the largest impact on the lowest layer in the ionosphere.
Primarily impacts satellite comms. Extreme levels can impact
cable systems, power grids, blow up power transformers, and cause (as
research indicates) increased geological activity (e.g., earthquakes,
See D-Region Absorption Prediction
page for current impacted frequencies in the D-Region. Aurora
Normalization factor (n) <2.0=high confidence, >2.0=low confidence