HAM Blog


Today at 20:45 I was scanning 40Meters and ran accross a radio broadcast on 7.275.000 – a station out of the far east somewhere. I have noticed a lot of interference from overseas lately. Sound clip here: perhaps someone could translate.

One the same subject, ARRL wrote up an article on this same issue.

From ARRL: http://www.arrl.org/news/stanag-4285-signal-showing-up-on-40-meters-other-intruders-spotted

STANAG 4285 Signal Showing Up on 40 Meters, Other Intruders Spotted

03/30/2017A STANAG 4285 intruder has been showing up on 7101.8 kHz, according to the International Amateur Radio Union (IARU) Region 1 Monitoring System (IARUMS).

“The signal was strong in South America, but rather weak in Europe,” the latest edition of the IARUMS newsletter reported. “We had the same problem in earlier times. Location probably Falkland Islands.”

Its unusual designation aside, STANAG 4285’s motorboat-like signals are pretty common on HF frequencies between about 2 MHz and 23 MHz. It is the data communication “modem” that North Atlantic Treaty Organization (NATO) military agencies use for the purposes of standardization, and it comes in several flavors (sub-modes), with a variety of speeds — from 75 bps to 3600 bps — and interleaving, both short and long. BPSK, QPSK, and 8PSK are used with STANAG 4285 for specific speeds. The waveform consists of an 1800-Hz carrier with PSK modulation.

It’s not unusual to hear STANAG-4285 signals around the world, not all of them from NATO stations. Most of the traffic is encrypted, but sometimes it is not, and software is available on the Internet to decode it.

IARUMS further reported that a Russian Air Force F1B (frequency-shift keying) intruder (REA4) was showing up on 7.018 MHz during February, but another F1B intruder on 7.193 MHz from Kaliningrad, Russia, was no longer active at the end of February. German telecommunication authorities had filed a formal complaint. No complaint is possible regarding another Russian F1B signal on 14.308 MHz, however; it is legal under a footnote to the ITU Radio Regulations that allocates 14.250 to 14.350 MHz to the fixed service on a primary basis in Armenia, Azerbaijan, China, Côte d’Ivoire, the Russian Federation, Georgia, Iran, Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan, and Ukraine. Reported splatter from Radio France International on 7.205 MHz has been cleared up.

An over-the-horizon radar from Asia is reported to be covering parts of 80 meters daily. Its likely location is China. A Chinese broadband OTH radar was observed on 20 meters, while the Russian systems-intelligence “Konteyner RLS” OTH radar, transmitting from in the Nizhny Novgorod region, is frequently spotted on 20 meters. It was reported disturbing parts of 40 and 20 meters, covering a 13-kHz swath of spectrum. Radio Hargaysa in Somalia is still being heard on 7.120 MHz, but the 7.175 MHz Radio Eritrea signal that was being interfered with from Ethiopia apparently is gone. Radio Taiwan and a Chinese jammer are being heard on 14.295 MHz.