Propagation & Band Conditions
Radio wave propagation changes constantly with solar activity, time of day, and season. The live solar-terrestrial data below shows current HF and VHF band conditions, solar flux, sunspot number, and geomagnetic activity — useful for planning when and where you are likely to make contacts.
Live Solar & Band Conditions
Solar-terrestrial data courtesy of Paul Herrman / N0NBH · hamqsl.com. Images update automatically.
Understanding the Numbers
- Solar Flux Index (SFI) — higher values (100+) generally mean better HF propagation on the higher bands (10–20 m).
- Sunspot Number (SN) — more sunspots usually improve high-band openings.
- A-index & K-index — measures of geomagnetic disturbance. Lower is better; high values can degrade HF and cause auroral conditions.
- Band conditions (Day/Night) — a quick “Good / Fair / Poor” read for each band segment.
Propagation Tools & Forecasts
- HamQSL Solar-Terrestrial Data (N0NBH)
- NOAA Space Weather Prediction Center
- PSK Reporter — real-time reception map
- DX Maps — real-time band openings
- VOACAP Online — HF propagation prediction
- SolarHam — space weather news
Feed Line, SWR & Return Loss
Getting your signal out efficiently matters as much as the band conditions. These references (originally shared by Dwight / N2FMC) cover RFI, ferrites, baluns, and how to interpret SWR and return loss on your feed line: