Solar Activity and HF Propagation

Solar Flux	K-index	HF Propagation Conditions
0-100	4-5	Poor
100-150	2-3	Good
150-200	0-1	Excellent
200-250	1-2	Very Good
250-300	0-1	Excellent
300-350	0-1	Excellent
350-400	0-1	Good
400+	0-1	Very Good