Beacon Monitor

What is the NCDXF/IARU International Beacon Project?

The International Beacon Project (IBP) is a network of 18 amateur radio beacons operated by the Northern California DX Foundation (NCDXF) together with the International Amateur Radio Union (IARU). The beacons transmit one after another on five HF bands, so a listener can judge propagation on a given path within a three minute window rather than guessing. Because the sequence is fixed and tied to UTC, the beacon on air at any instant can be calculated exactly, which is what the monitor above does.

How the three minute beacon cycle works

Each beacon transmits for 10 seconds on one band, then moves to the next band while the following beacon takes over the frequency it just left. With 18 beacons and 10 second slots, one full cycle takes 180 seconds, or exactly three minutes. Every transmission is the beacon callsign sent in CW at 22 words per minute, followed by four one second dashes. The callsign and the first dash are sent at 100 watts, the remaining three dashes step down to 10 watts, 1 watt and 0.1 watt, so the number of dashes you can still copy tells you how strong the path really is.

NCDXF beacon frequencies

Band	Frequency
20 m	14.100 MHz
17 m	18.110 MHz
15 m	21.150 MHz
12 m	24.930 MHz
10 m	28.200 MHz

The 18 IBP beacons in transmission order

The beacons always transmit in the order below. Slot 1 starts each three minute cycle on 14.100 MHz at 00, 03, 06 minutes past the hour and so on.

Slot	Callsign	Location	Grid
1	4U1UN	United Nations, New York	FN30AS
2	VE8AT	Eureka, Nunavut, Canada	EQ79AX
3	W6WX	Mt Umunhum, California	CM97BD
4	KH6RS	Laie, Oahu, Hawaii	BL10TS
5	ZL6B	Masterton, New Zealand	RE78TW
6	VK6RBP	Rolystone, Perth, Australia	OF87AV
7	JA2IGY	Mt Asama, Japan	PM84JK
8	RR9O	Novosibirsk, Russia	NO14KX
9	VR2B	Hong Kong	OL72BG
10	4S7B	Colombo, Sri Lanka	MJ96WV
11	ZS6DN	Pretoria, South Africa	KG44DC
12	5Z4B	Kikuyu, Kenya	KI88HR
13	4X6TU	Tel Aviv, Israel	KM72JB
14	OH2B	Lohja, Finland	KP20EH
15	CS3B	Santo da Serra, Madeira	IM12OR
16	LU4AA	Buenos Aires, Argentina	GF05TJ
17	OA4B	Lima, Peru	FH17MW
18	YV5B	Caracas, Venezuela	FK60NK

How to find the beam heading to a beacon

Enter your Maidenhead locator in the box at the top of this page and the monitor calculates the great circle bearing and distance from your station to every beacon. Point a directional antenna at that bearing to give yourself the best chance of hearing the beacon, and remember that the reciprocal path works the same way: if you can hear a beacon well, stations in that part of the world can probably hear you.

Frequently asked questions

Which beacon is transmitting right now?

The monitor at the top of this page shows the beacon currently on air for each of the five bands, updated every second from UTC. Because the IBP schedule is fixed, no internet connection to the beacons is needed: the current beacon is derived from the clock.

What frequencies do the NCDXF beacons use?

The five IBP frequencies are 14.100 MHz, 18.110 MHz, 21.150 MHz, 24.930 MHz and 28.200 MHz, covering the 20, 17, 15, 12 and 10 metre bands.

How long does each beacon transmit?

Each beacon transmits for 10 seconds on each band. With 18 beacons in the network, a complete cycle lasts three minutes, so any given beacon returns to the same frequency every three minutes.

What power do the IBP beacons run?

Each transmission steps down in power: the callsign and first dash are sent at 100 watts, then the three remaining dashes at 10 watts, 1 watt and 0.1 watt. Hearing all four dashes indicates a much stronger path than hearing only the callsign.

Do I need a beam antenna to hear the beacons?

No. The beacons use vertical omnidirectional antennas and are regularly copied on simple wire antennas such as dipoles and end fed halfwaves. A directional antenna simply improves the odds on marginal paths.