ARUMS Intruder Watch Reports “Burst Signal” from China

ARUMS Intruder Watch Reports “Burst Signal” from China

The International Amateur Radio Union (IARU) Region 1 Monitoring System (IARUMS) reports that in addition to the already well-known intruders, some new or rarely heard signals have been spotted, including a burst signal from an over-the-horizon radar (OTH-R) in China. The IARUMS July newsletter reported that this signal — in 3.8 second bursts — was encountered repeatedly on different 40-meter frequencies as well as on 20 meters.

NATO (North Atlantic Treaty Organization) military systems were more active in various amateur bands using a variety of modes, such as MIL188-110A, LINK 11 CLEW and SLEW, STANAG 4285, STANAG 4481-FSK, and MIL188-14A ALE.

FSK-ARQ and PSK-ARQ emissions with typical 600 baud, 600 Hz, or even 1200 Hz, have been conspicuous for some time. These are known as DPRK 600 and 1200, respectively, and are attributed to North Korea. For many days, a LINK 11 CLEW station was active on 7159.0 kHz in DSB mode (double sideband, 6 kHz wide), at times causing heavy interference.

Predominant over-the-horizon radars monitored included the Russian Container, as well as the British PLUTO system from Cyprus, generating annoying interference. On 14301.9 kHz, an orthogonal frequency division multiplexing (OFDM) 60 signal could be found occasionally.

Some broadcasters interfere regularly. Radio France Internationale on 7205 kHz splatters down to 7186 kHz, 2100 – 2200 UTC. The Voice of Broad Masses is regularly found on 7140 and 7180 kHz. China Radio International is often found on 14000 kHz, and Sound of Hope from Taiwan is sometimes audible if conditions permit, but the signal is often jammed.