HF beacon tracker
Eighteen beacons around the world take turns on five HF frequencies on a fixed schedule, so a few minutes of listening shows where a band is open. See who is transmitting now, what they are sending, and how far away they are.
On the air now
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Timed from this device's clock. The beacons are timed to the second; if what you hear is ahead or behind, adjust here.
Distances and headings are worked out in this browser; your grid is not sent anywhere.
14.100 MHz 20 m
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18.110 MHz 17 m
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21.150 MHz 15 m
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24.930 MHz 12 m
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28.200 MHz 10 m
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Strips show the 10-second transmission to scale: the call sign in Morse at 100 W, then the four one-second dashes, each drawn shorter for each 10 dB step down in power. The line is now.
Where they are from you
Enter your grid square above to see each beacon's distance and heading on a map centered on you.
Follow one beacon
4U1UN is silent this slot.
| Frequency | Each cycle starts at | Next (UTC) |
|---|---|---|
| 14.100 MHz 20 m | 0 min 00 s past each three minutes | |
| 18.110 MHz 17 m | 0 min 10 s past each three minutes | |
| 21.150 MHz 15 m | 0 min 20 s past each three minutes | |
| 24.930 MHz 12 m | 0 min 30 s past each three minutes | |
| 28.200 MHz 10 m | 0 min 40 s past each three minutes |
Three-minute cycles start on the hour and every three minutes after, so 4U1UN is heard on each frequency 20 times an hour.
Hear a transmission
One transmission by 4U1UN as the controller sends it: the call sign at 22 words per minute, then the four power steps. Loudness follows the power, so turn the volume up: the last dash is 30 dB below the first, as it would be on the air. Choose another beacon in "Follow one beacon".
- Call sign and first dash: 100 W, reference level
- Dash 2: 10 W, 10 dB down
- Dash 3: 1 W, 20 dB down
- Dash 4: 100 mW, 30 dB down
Try this
Each button sets up the tracker and says what to notice.
Apply it
- Listen on one beacon frequency for three minutes and note which beacons you hear: that shows where the band is open from you right now. Listen across all five to find the best band toward one part of the world (NCDXF).
- You do not need to copy the 22 words per minute call sign: the schedule tells you which beacon is transmitting (NCDXF).
- The beacons run 100 W into a vertical antenna, so even a weak one can mean a path that works well for a station with more power or a directional antenna (NCDXF).
- Keep these five frequencies clear. The IARU HF band plans set them aside for the beacons; NCDXF notes that this is law in some countries and recommended practice in others (NCDXF FAQ). In the US it is a band plan convention, not an FCC rule, and the General exam asks why you should avoid transmitting on them (G1E10).
- Compare what you hear with current conditions on the propagation tool. Silence usually means the path is closed, but NCDXF asks to hear about a beacon its status list shows as off the air that you hear anyway, or one that is malfunctioning (NCDXF schedule).
How it works
- The beacons use 14.100, 18.110, 21.150, 24.930 and 28.200 MHz. Each transmission lasts 10 seconds; then every beacon moves up one frequency and the next in the sequence starts on 14.100, so each beacon is on each frequency once every three minutes.
- A transmission is the call sign at about 22 words per minute (54 ms code elements) and four one-second dashes at 100 W, 10 W, 1 W and 100 mW, each 10 dB below the one before. The strips and the player use this timing from the beacon controller description.
- The three-minute cycle divides a day evenly, so cycles start on the hour. The page uses this device's clock; adjust it if what you hear is early or late.
- Off-the-air status is a dated copy of the project's status file, which NCDXF asks apps to cache rather than fetch for every user. Check the live schedule for today's status.
- Distances and headings are great-circle values from the centers of your grid square and of each beacon's grid square, on a sphere.
Learn more: How radio signals travel
Sources: NCDXF/IARU International Beacon Project: Transmission Schedule (Northern California DX Foundation); NCDXF/IARU International Beacon Project: Locations and Grid Squares (Northern California DX Foundation); NCDXF/IARU International Beacon Project: Introduction (Northern California DX Foundation); NCDXF/IARU International Beacon Project: FAQ (status file) (Northern California DX Foundation); NCDXF/IARU International Beacon Project: Beacon Controller (transmission timing) (Northern California DX Foundation); 2023-2027 General question pool (G1B03, G1E10, G2D04) (NCVEC Question Pool Committee)
Practice the exam questions: G1 Commission’s Rules (General), G2 Operating Procedures (General), G3 Radio Wave Propagation (General)
Found something wrong or out of date? Report a problem with this tool on GitHub (a public issue; nothing is sent until you submit it there).