In the app
For radio amateurs, Almanaccolo shows the state of the ionosphere and HF band conditions, day and night, continuously updated.
Shortwave reaches the other side of the world by bouncing off the ionosphere, a layer of gas the Sun ionises. The more active the Sun, the higher in frequency that layer reflects: with a solar flux above 150, the 10-metre band opens and you work Australia on a few watts.
The combination every operator hopes for is high solar flux and a K index near zero. High flux raises the maximum usable frequency; a high K means a disturbed magnetic field, which absorbs signals especially on polar paths.
| Band | When | Typical reach |
|---|---|---|
| 160–80 m | Night | Regional and continental, best in winter. |
| 40 m | Night and dawn | Europe by day, intercontinental at night. |
| 20 m | Day | The DX band: open almost always. |
| 15 m | Day | Excellent with high solar flux. |
| 10 m | Day | Opens only at solar cycle maximum. |
Data: hamqsl.com
It measures solar activity at 10.7 cm wavelength. The higher it is, the higher in frequency the ionosphere reflects: above 150 the 10-metre band opens and you work Australia on a few watts.
40 metres for intercontinental contacts, 80 and 160 for regional ones. The high bands — 20, 15 and 10 metres — live on sunlight and close at night.
Free app
Almanaccolo greets you each morning with the almanac of the day, sunrise and sunset times and your saved events.
