Mode HF beacons

HF beacons: what is open from here, band by band.

Group	HF utility
Default frequency	14.5 MHz
Default sample rate	10 Msps
In the mode list	NCDXF/IARU, Long Dashes, single letters

Step-by-step: Tutorial-HF-beacons

What HF beacons is

The NCDXF/IARU International Beacon Project transmits on five HF frequencies in a fixed rotation, so you can tell at a glance which bands are open to which parts of the world.

Frequencies and settings

Setting	Value
Start frequency	14.5 MHz
Tuning range of the mode table	0.5 to 30 MHz
Sample rate asked	10 Msps
Lowest working rate	250 ksps
Channel width	8 MHz

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is NCDXF/IARU, Long Dashes, single letters.

What OnAir shows

HF beacon propagation monitor: which NCDXF/IARU International Beacon Project beacons (18 beacons on 14.100, 18.110, 21.150, 24.930 and 28.200 MHz, 10 s slots), Australian Long Dashes and Russian single-letter beacons can be heard from here, by band, with SNR, distance and bearing, a great-circle map and 24 hour history; an editable beacon list; clicking a beacon tunes and listens.

The mode's own tab has these screens: Beacons, Bands open, Map, History, Settings. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• This is a tool for looking at the spectrum and recordings, not a decoder of one standard.
• Which radio: An RTL-SDR can receive HF only in direct-sampling mode, which OnAir offers in its radio settings; results depend on the antenna. SDRplay and Airspy HF+ radios are better suited.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: Some HF utility traffic belongs to governments or the military. Receiving is legal in many countries, but rules differ. Check them where you live. See Legal.

Related pages

• All modes, HF utility
• Supported radios, Troubleshooting, FAQ
• More in HF utility: Datawell Buoy HF Link, CODAR / HF ocean radar, HF ALE