The International Amateur Radio Union Region 1 Monitoring System (IARUMS) April newsletter chronicles a plethora of intruding signals heard on exclusive Amateur Radio allocations in Europe and Africa, many of these also affecting the bands in IARU Regions 1 and 3.

The most significant interfering signals originate from over-the-horizon (OTH) radars in China and Russia and affect 40, 30, 20, and 15 meters.

The newsletter also recounts monitoring stations’ reports of voice traffic on several bands from fishing operations in various parts of the world, telemetry from marine buoys, and persistent taxi dispatching traffic from Russia on 10 meters.

Other interference has stemmed from broadcasters — harmonic-challenged and otherwise — as well as from jamming signals attempting to prevent broadcasts from reaching their intended audience. Pirate (ie, unlicensed) stations have been reported on 80 meters and elsewhere, and Russian digital military traffic has been monitored on 40 and 20 meters.

OTH radar interference prevails, however. IARUMS Region 1 Coordinator Wolf Hadel, DK2OM, documented a Chinese OTH radar occupying considerable swaths of spectrum on several bands. IARU Region 1 maintains the world's most active network of volunteer intruder monitors.