Band Conditions
Understanding HF band status is essential for choosing where to operate. Each band has different characteristics and responds differently to solar and geomagnetic conditions.
Band Characteristics
| Band | Freq. | Characteristics | Best Use |
|---|---|---|---|
| 160m | 1.8 MHz | Night only, gray line critical | Winter night DX |
| 80m | 3.5 MHz | Night, noisy in summer | EU/regional night |
| 40m | 7 MHz | 24h, DX at night | All-around band |
| 30m | 10 MHz | Similar to 40m, CW/digi only | CW and FT8 |
| 20m | 14 MHz | Main DX band | Daytime DX |
| 17m | 18 MHz | Less crowded than 20m | DX with less QRM |
| 15m | 21 MHz | Requires moderate SFI | DX with medium-high cycle |
| 12m | 24 MHz | Requires high SFI | DX with high cycle |
| 10m | 28 MHz | Open only with high cycle | Exceptional DX when open |
Interpreting Status
A band's status can be:
- Open: reliable propagation, strong signals
- Marginal: weak signals, unstable propagation
- Closed: no ionospheric propagation
A band can be open toward some directions and closed toward others!
Daily Cycle
Bands follow a predictable daily cycle:
- Sunrise: higher bands start opening toward east
- Morning: 20m-15m active, low bands closing
- Noon: maximum ionization, possible 10m opening
- Afternoon: stable conditions on mid bands
- Sunset: higher bands closing, 40m becomes DX
- Night: 40m-80m-160m for DX, higher bands closed
Practical Tips
To choose the right band:
- Check indices: high SFI = try higher bands
- Watch DX Cluster: see where spots are
- Listen to beacons: objective propagation verification
- Experiment: sometimes bands surprise you!
- Consider season: 10m is better in fall-winter