The Soviet era Woodpecker.
In July 1976, about 5 years after I gained my amateur radio licence there appeared on the shortwave (SW) bands, especially on 20 metres, a strange tap-tap-tap sound. It appeared quite randomly, at different times and frequencies and completely obliterated about 50 KHz of any SW band. It was nicknamed the “Woodpecker”. It was extremely strong and in New Zealand seemed to be coming from a North Easterly direction. It transpired that this interference was being created by the Soviet Union as a result of an “Early Warning System” of US missile attacks. It was an “Over the Horizon Radar” (OTH) system, running about 10 megawatts (nearly 13,500 thousand horsepower!) into gigantic antennas. It functioned by bouncing extremely high energy radio signals off the ionosphere, thereby overcoming the limitations of conventional radar which can only “see” to the horizon.
There were two such installations built, one near Chernobyl (DUGA-1) and one in Siberia (DUGA-2). It’s assumed that the Chernobyl nuclear power station was built primarily to supply the required power for DUGA-1. The antenna systems used were absolutely huge, 700 meters long, 150 meters high consisting of hundreds of phased arrays of broadband HF antennas. It’s difficult to estimate the gain of the antennas but it would have been 20-30db, maybe more, meaning an Effective Radiated Power (ERP) of 1 to 10+ gigawatts! It was always sobering to reflect on how such sheer power and antenna gain could absolutely flatten the DX portion of a totally quiet and dead band with S9+30db QRM! It was like having 10 local lightning strikes a second.
For those that understand radio propagation physics and the level of engineering required to do this, it was and still remains all quite mind-boggling.
The transmissions frequency hopped, particularly targeting frequencies in the amateur radio bands which were usually relatively interference free due to international agreements. So, the Soviets targeted these frequencies rather than try to compete with the shortwave broadcast stations. One would never hear the Woodpecker interfering with Radio Moscow, for example! This system also caused harmful interference to many essential services outside the amateur bands, but world-wide complaints fell on deaf ears. International airline communications traffic, marine communications and many other such essential services were affected.
The Duga systems stopped operating in 1989 along with the collapse of the Soviet Union. They had operated for 13 years, at huge expense, had created much chaos on the shortwave radio bands and all for what? Not a single enemy missile was ever detected and much more harm was done to the Soviet citizens by the ill-fated Chernobyl reactor meltdown than any realistic threat the USA ever posed.
