KC3ARC .ORG
☀️ Band Conditions and Propagation
Stay informed with real-time solar data, propagation indicators, and band conditions for amateur radio operators.
K-Ind
K-Index – indices from observatories around the globe updated every three hours.
0 and 1 represent quiet magnetic conditions equal good HF band conditions, subject to a sufficient level of solar flux.
2 and 4 indicate unsettled or even active magnetic conditions, reflected in a degradation of HF conditions.
5 represents a minor storm.
6 larger storms.
7 – 9 represents a very major storm that would result in a blackout of HF communications.
A-Ind
A-Index – Daily Average of Magnetic Activity
0 to 3 Represent quiet magnetic conditions, thus good HF band conditions.
4 Quiet to unsettled
7 Unsettled
15 Active – active magnetic conditions, reflected in a degradation of HF conditions.
27 Active – active magnetic conditions, reflected in a degradation of HF conditions.
48 Minor storm
80 Major storm
132 Severe storm
208 Very major storm – blackout of HF communications
400 Very major storm – blackout of HF communications
SFI
Solar Flux Index (SFI) measures the sun’s radio emissions at a wavelength of 10.7 cm (2800 MHz).
70 – Not Good
80 – Good
90 – Better
100+ – Best
KCARC – Kent County Amateur Radio Club
Dover, Delaware
501(c)(3) Nonprofit