Not All “Intruders” on Ham Bands are Illegal — But a Lot of Them Are


The monthly newsletter of the International Amateur Radio Union Region 1 Monitoring Service (IARUMS) typically makes for some interesting reading. While the reports that come from more than two dozen contributors in Europe and Africa can be a bit visually dense, the content conveys the impression that that there are myriad intruders on the Amateur Radio bands. However, not all of them are illegal, as IARUMS points out, but a lot of the signals heard are not supposed to be where they were monitored. The individual reports can be a bit humorous too.

“Get the grub, and I’ll talk to you later this evening,” was a snippet of a conversation between two fishermen — identified as Mick and Jack — that an Irish Radio Transmitters Society (IRTS) monitor overheard on 3.570 MHz and reported to the IARUMS. The IRTS said the chatter was accompanied on both sides by “loud motor noise,” and, if that were not sufficient detail, it pointed out that both men had Galway accents. Intruding signals from fishing crews throughout IARU Region 1 are commonplace.

More blatant are the repeat offenders, such as the “Chinese foghorn” heard by over-the-horizon (OTH) radars on several frequencies in the exclusive Amateur Radio 20-meter allocation, as well as on 15 and 40 meters. IARUMS Region 1 Coordinator Wolf Hadel, DK2OM, said the signals, 10 kHz wide and with 50 and 66.66 sweeps per second, transmit in burst mode and often jump frequencies.

Some signals from military stations on non-exclusive Amateur Radio allocations are legal. For example, the latest IARUMS newsletter cites the Stanag-4285 military signal that showed up for a few days in August on 5,361.8 kHz. The Stanag-4285 transmissions, coming from a Navy facility in Aarhus, quit on August 28. “Many thanks to the Danish Navy for leaving this frequency!” Hadel added, noting that the Danish Navy is a primary user. “We have to respect primary users!” he said.

An Australian OTH radar…

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