India’s Over the Horizon Radar has raised concerns within the amateur radio community. International Amateur Radio Union (IARU) Region 1 Monitoring System (IARUMS) newsletter have raised concerns over this development.
This news originally surfaced on Alpha Defense in June 2021 stating that Defence Research and Development Organisation (DRDO) is working on an Over the Horizon Radar system to keep a close eye on Chinese movements in the Indian Ocean region.
“Over the Horizon Radars (OTHR) often massively interfere with amateur radio,” the IARU Region 1 report said, citing the well-known Russian “Contayner” OTHR, an OTHR at the UK base in the Republic of Cyprus, and others in Iran and China. “They are present daily on several frequencies within the exclusive amateur radio HF bands,” IARU Region 1 said.
The best-known Chinese OTHR — called “Foghorn” because of its distinctive sound — has signals at varying sweep rates that occupy 10 kHz of spectrum. The IARUMS newsletter reported other OTHRs occupying 160 kHz of bandwidth with 10 scan-per-second rates.