Intruder Watch Coordinator

The RSGB Monitoring system reports unauthorised transmissions to Ofcom and IARU Region 1

The RSGB Monitoring system reports unauthorised transmissions to Ofcom and IARU Region 1

The Intruder Watch Coordinator runs the RSGB Monitoring System—part of the IARU Monitoring System


Vaughan Ravenscroft, M0VRR


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The RSGB Monitoring System, more popularly known as the Intruder Watch, forms part of the IARU Monitoring System.

As such it submits reports of non-amateur transmissions heard on the exclusive HF amateur bands to both the Ofcom Monitoring Station at Baldock and IARU Region 1.

Intruders removed from the 14MHz band as a direct result of Intruder Watch reports being acted on by Baldock include two Russian broadcast station harmonics and a French military data transmission.

On 18MHz the list includes an Argentine weather fax, military stations in Somalia and India, and diplomatic stations located at foreign embassy stations in Paris, Ankara and New Dehli.

Other non-data categories of intruding signals include CW, broadcast stations, speech, and over-the-horizon radar (OTHR).

Any report should include as much information as possible, but preferably frequency, date, time (UTC), mode of transmission, any identification signal or callsign, language used, text—where appropriate—and beam heading where possible.

For data transmissions a ‘zero beat’ frequency will be accurate enough for monitors without decoders.

This information can then be passed on to a suitably equipped monitor for further investigation.

Most information received by the Intruder Watch Coordinator arrives from regular monitors, but occasional reports are also welcome from any one who finds what may be an intruding signal on one of our exclusive amateur bands.

All reports are welcome and will be acknowledged.