Between 1976 and 1989, the USSR operated a radar system that became known as the “Russian Woodpecker.” It was a type of “over the horizon” (OTH) radar known as the DUGA-3. It operated on frequencies populated by shortwave broadcasts and amateur operators and produced a very strong signal that produced a tapping sound similar to a woodpecker, hence the name. The Russian Woodpecker was phased out and replaced with satellite technology. The signal was not heard again until recently.
One day while browsing Reddit’s /r/amateurradio “subreddit,” I found a post where a user recorded a strange signal in the 20 meter band and suggested it was an over-the-horzon radar. I switched my receiver on the very next day and heard the same signal. This particular sound wasn’t like the Russian Woodpecker, but it was an unusual signal that lasted 30 seconds or so. My Android was sitting on the desk and I was able to capture a recording. I left the radio on all day with the volume turned up so I could listen for the signal while I went about my day. At about five minutes to midnight, a very strong signal blasted through the speaker. It sounded EXACTLY like the recordings I’d heard of the Russian Woodpecker. Unfortunately, my Android was in the next room and the signal was gone before I could record it.
I’m certainly not an expert in amateur radio. I’ve only been dabbling with it for about four years, but this signal seemed unique. It didn’t sound like usual sources of interference that normally originate from inside or near the home, like AC power adapters, lights, transformers and similar devices. I revisited the subreddit and searched around the net for answers. It turns out that I wasn’t alone, and there was quite a bit of chatter on the topic.
Since the summer of 2013, Russia has been operating the 29b6 radar, another over-the-horizon system. Most radar, like what we’re used to seeing at airports and in police cars, transmits a signal along the line-of-sight, like a searchlight. OTH uses the ionosphere to reflect the signal over the curvature of the earth in the same manner that amateur radio operators communicate with each other over very long distances. From what I’ve come to understand, what I heard was a sounding or sampling signal from 29b6 radar system that is used to adjust the radar for maximum efficiency. Some reports indicate that it became more active during heightened military activity. Other sources indicate that Iran and China are deploying similar systems that can be heard in the USA.
The original DUGA-3 lies in ruins near Chernobyl, so this isn’t a refitting of the old system. It’s completely new and apparently uses newer technology. Old hams who operated during the DUGA-3 days are not happy to see OTR on the air again, as the interference sometimes makes for tough conditions. If you’re interested in jumping through the rabbit hole, there are videos of Russian news reports on the new radar, tours of the old DUGA-3 along with plenty of foil-hat theories to dig through. If you’d like to hear it for yourself, tune somewhere around 14.270 on a shortwave and see if it pops up.