"Intruders" Spotted in Several Amateur Radio HF Bands

NEWINGTON, CT, July 5, 2006--An apparent "intruder" signal spotted on 20 and 17 meters -- possibly originating from a Chinese HF broadcast station -- has sparked a slew of reports and complaints from around the globe. In addition, those who volunteer to monitor the bands for out-of-place signals cite reports of so-called Russian "single-letter beacon" stations on 40 meters. As the League's liaison with the International Amateur Radio Union (IARU) Region 2 Monitoring System (IARUMS) -- also known as "Intruder Watch" -- ARRL Field and Regulatory Correspondent Chuck Skolaut, K0BOG, is often the first to hear about strange signals that suddenly pop up on the bands.

"It was still on 18.160 MHz as of July 2," Skolaut said, citing radio amateurs' reports of a "Chinese broadcaster" on 17 meters. "I haven't received any more recent 20 meter reports since June 30, when it was heard on 14.260 MHz." The signal has been heard on one band or the other in the US from the Northeast to Hawaii, as well as in Toronto, Canada, Sri Lanka, the UK, Germany, Australia, Hong Kong and India.

IARU Region 2 Monitoring System Coordinator Bill Zellers, WA4FKI, says Intruder Watch is a lot like the neighborhood watch programs many communities set up with local law enforcement. "The concerned members of the Amateur Radio community organize and form their own neighborhood watch program called Intruder Watch." Zellers stresses that monitors are not "frequency police." They can only report what they hear.

Regarding the apparent Chinese intruder, monitors in Connecticut and Pennsylvania reported a strong signal from the apparent AM broadcaster on 18.160 MHz on July 2 at 1100 UTC and 1300 to 1400 UTC. The 20-meter signal has been heard on 14.180 MHz as well. Several listeners say their bearings put the source of the signal in central or southern China. Chris Cummings, G4BOH, says he's been able to match the audio to transmissions appearing on 15.495, 11.665 and 12.025 MHz. He filed a report with Ofcom, the UK's telecoms regulatory agency.

Jammers?

Reports filed with DX Listening Digest suggested that the 14.180 and 18.160 MHz broadcasts are intended to jam the clandestine "Sound of Hope" transmission from Taiwan. July 2 DX Listening Digest reports put the Chinese-language broadcasts appearing on 14.310 MHz -- QRMing the Medical Amateur Radio Council (MARCO) net on 14.308 MHz -- as well as on 18.160 MHz. Short wave listeners (SWLs) say the AM carrier occasionally drops at the top of the hour for a monitoring check, only to reappear five minutes later.

Skolaut has shared reports and updates with the FCC, although as he and Zellers point out, the Commission has no authority to make intruder stations outside the US stop transmitting on Amateur Radio frequencies. Such situations typically are dealt with through diplomatic channels.

Allocation Complications

One thing that complicates intruder watching on HF is that Amateur Radio allocations vary from one ITU region to another and even within regions. Intruder Watchers can only concern themselves with exclusive allocations. Some domestic Amateur Radio HF allocations, such as 7.1 to 7.3 MHz outside Region 2, are shared with other services or unavailable to hams, while only 7.0 to 7.1 MHz currently is allocated exclusively to the Amateur Radio Service worldwide.

On other ham radio HF allocations, such as the 30-meter band, Amateur Radio is secondary to other users. The 20, 17, 15, 12 and 10-meter bands are allocated exclusively to the Amateur Radio Service worldwide.

Russian Beacon Stations

For several years now, monitors around the world have reported the presence of "single-letter markers" or "single-letter beacons" apparently emanating from Russia. The so-called "C" beacon has again been reported active on 7.039. Those familiar with the beacons -- believed to be Russian Navy channel markers -- say there has been a "beacon cluster" on and around 7.039 MHz in the past. These stations identify with a single letter in conventional Morse code.

A station in Oregon recently reported hearing the "M" beacon on or about 7.039 MHz. That transmission reportedly comes from Asiatic Russia.

Invitation to Join

Zellers invites other radio amateurs or SWLs in IARU Region 2 (the Americas and some eastern Pacific Islands) to become part of the Intruder Watch program. He explains that IARUMS volunteers listen on the bands for intruders. IARU monitors have no legal authority but act only as band monitors, he points out. Zellers recently noted that Over the Horizon Radar (OTHR) stations operating within Amateur Radio HF bands between 3 and 30 MHz sometimes make it difficult to work DX from some parts of the US.

Monitors in other parts of the world have logged "drift net buoys" on 160 meters, international broadcasters on 80 and 40 meters, fishing trawlers and pirates, paramilitary stations from India on 17 meters as well as something called "the Havana Gurgle" -- the third harmonic of a broadcast on 6.030 MHz.

In 2001, transmissions from a Coastal Ocean Dynamics Applications Radar (CODAR) -- an ocean current-mapping technology used in meteorological and commercial applications -- caused QRM on 12 meters. The CODAR site, in Honduras, was notified, and the problem ceased.

"To survive, the Amateur Radio community needs clean frequencies that are free of intruders," Zellers says. "Take a few minutes to join the Intruder Watch program and help us take care of our Amateur Radio neighborhood." Contact Zellers for more information.

Previous: ARRL's "The Big Project" Tops 170 Schools

Next: Contest Club Finland to Provide Running WRTC-06 "Scoreboard"