International Beacon Project

The International Beacon Project (IBP) is a global network of 18 continuous wave (CW) beacons that transmit on five set frequencies within the high frequency band. Its purpose is to help amateur and commercial HF radio users gauge current ionospheric signal propagation conditions. The Northern California DX Foundation (NCDXF) and the International Amateur Radio Union (IARU) jointly coordinate the project.

History

The first beacon began operating in 1979 from Northern California. It transmitted a one-minute signal every ten minutes on 14.1 MHz, using custom-built transmitter and controller hardware. The signal included the beacon’s call sign in Morse code at 100 watts, four nine-second dashes at 100, 10, 1, and 0.1 watts, and a sign-out at 100 watts.

The NCDXF and seven partner organizations from the United States, Finland, Portugal, Israel, Japan, and Argentina ran the initial network. Because building beacon hardware proved difficult, each site used a Kenwood TS-120 transceiver controlled by a custom beacon controller. The network operated solely on 14.1 MHz, and the beacon format remained unchanged.

In 1995, work began to upgrade the network to operate on five designated HF frequencies. The new beacons used Kenwood TS-50 transceivers with an upgraded controller. The number of partner organizations grew to 18, and a new ten-second beacon format was adopted.

Notable Projects

Beyond aiding amateur radio operators, the project has helped scientists study the ionosphere, improve propagation prediction models, and assist with radio direction finding.

Frequencies and transmission schedule

The beacons transmit continuously on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. Each beacon sends its signal once on each frequency, starting at the lowest and moving to the highest, followed by a 170-second pause while other sites transmit on the same frequencies.

The cycle then repeats. Each ten-second transmission consists of the beacon’s call sign sent at 22 words per minute, followed by four dashes. The call sign and first dash are sent at 100 watts; the next three dashes are at 10, 1, and 0.1 watts. All transmissions are coordinated using GPS time, so all 18 beacons transmit in succession on a given frequency once every three minutes.

Hardware

The hardware uses commercial HF transceivers (Kenwood TS-50 or Icom IC-7200) keyed and coordinated by a purpose-built beacon controller.