Over the Horizon Radars Becoming Routine Visitors on Amateur HF Bands
The International Amateur Radio Union Region 1 (Europe/Africa) Monitoring System (IARUMS) reports a spate of over the horizon (OTH) radar signals on various Amateur Radio HF bands — exclusive and shared. Many of these signals are being heard outside of the Region 1 confines.
A 50 kHz wide Russian OTH radar has been heard in the evening on 80 meters, often in the CW part of the band. An “often long-lasting” Russian OTH signal about 13 kHz wide is being heard on the 7000-7100 kHz segment of 40 meters, while some digital traffic (FSK or PSK), and a “Codar-like radar from the Far East” are being heard in the 7000-7200 kHz segment as well as non-amateur CW transmissions.
The same OTH radar being heard on 40 meters also is appearing on 20 meters, along with digital traffic in FSK or PSK and on CW and broadband OTH radar signals from China. Some monitoring reports are intriguing, such as this one on 14.280 MHz from IARU Region 1 Monitoring System Coordinator Wolf Hadel, DK2OM: “Female voice with encrypted msgs — figures — “SZRU” = Foreign Intelligence Service of Ukraine in Rivne — every Wednesday at 1005 UTC.”
Broadband OTH radars from China, Australia, Cyprus, and Turkey have been monitored in 15 meters. On 10 meters, radars from Iran with FM CW and different sweep rates have been monitored, as well as fishery buoys on CW, and taxi operations on voice from Russia.
Voice traffic from fishing operations has been heard on all or most HF bands, as well as a variety of broadcasters, including the third harmonic of Radio Tajik (4765 kHz) on 14.295 MHz, Radio Taiwan and Myanmar Radio, both on 7.200 MHz, and Radio Hargaysa in Somalia on 7.120 MHz.