Live ham radio propagation
Current space weather from NOAA and a quick read of how the shortwave bands should behave. It refreshes every 10 minutes.
- Solar flux (SFI)
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- Higher numbers open the upper bands
- Sunspot number
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- Latest monthly value
- Planetary K index
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- Below 4 is best for HF
Estimated band conditions
A rule-of-thumb estimate from solar flux and the K index. Real conditions vary by season, path and time, so treat it as a guide.
| Bands | MHz | Daytime | Nighttime |
|---|---|---|---|
| 80 and 40 m | 3.5 to 7.3 | Loading | Loading |
| 30 and 20 m | 10.1 to 14.35 | Loading | Loading |
| 17 and 15 m | 18.1 to 21.45 | Loading | Loading |
| 12 and 10 m | 24.9 to 29.7 | Loading | Loading |
Solar flux
A measure of the sun's radio noise. More flux ionizes the upper atmosphere more, which lets higher bands bounce signals around the world.
K index
Rates disturbance in Earth's magnetic field from 0 to 9. When it climbs, shortwave signals fade and get noisy.
What about GMRS?
GMRS is UHF and mostly line of sight, so space weather barely touches it. Your antenna height matters far more.