HF Propagation



SFI (Solar Flux Index) — Higher is better

70 Poor
80 Good
90 Better
100+ Best

Higher solar flux values generally suggests better propagation on the 10, 12, 15, 17, and 20 meter bands. Solar flux rarely affects the 30, 40, 60, 80, and 160 meter bands.

A Index — Lower is better

1 to 60 Best
7 to 9 Good
11 or more Poor

Lower A-index values generally suggests better propagation on the 10, 12, 15, 17, and 20 meter bands.

K Index — Lower is better

0 to 1 Best
2 Good
3 to 4 Poor
5 Very poor