Propagation Conditions

Quick Reference:
SFU < 70: Low — HF bands above 40m unusable. 2200m/630m/160m/80m active at night.
SFU 70–90: Poor to fair — up through 20m, 60m/40m active.
SFU 90–120: Fair — up through 15m.
SFU 120–150: Fair to good — up through 11m/10m.
SFU 150–200: Excellent — 11m/10m open, 6m possible.
SFU > 200: High — reliable all HF/VHF bands through 6m.
K 0–2: Quiet — optimal conditions, no HF impact.
K 3–4: Unsettled — minor fading at higher latitudes.
K 5: Minor storm — noticeable HF absorption/noise.
K ≥ 6: Major+ storm — significant HF blackout risk.

Legend: ✓ Good · ≈ Fair · ✗ Poor
If SFI not entered, estimated from SSN.