The notorious over-the-horizon radar that played havoc with shortwave radio began transmissions in July 1976 and continued for more than 13 years.
When first heard by radio amateurs around the world it had a distinctive sharp, repetitive tapping noise. This resulted in them nick-naming it the 'Russian Woodpecker', and that name stuck.
It randomly hopped on frequencies to disrupt legitimate broadcasts, Amateur Radio, the marine and aviation bands, and utility stations, resulting in thousands of complaints by many countries worldwide.
Transmissions were heard from about 3 MHz to above 17 MHz and were officially part of the Draga radar system. In fact, there were three Russian Woodpecker transmitters strategically placed in Ukraine and Siberia. Each had a power of at least 10 megawatts feeding very large multi-element phased array antenna, which in official circles were called the 'steel yard'.
The Woodpecker signals bounced back from the ionosphere, and this backscatter contained information which could show any travelling object. At the height of Woodpecker nuisance some receivers were fitted with 'Woodpecker Blankers' to minimise the harmful interference.
The radars were part of the cold-war and until the fall of the Soviet Union formed part of the Anti-Ballistic Missile early-warning system network. The Russian Woodpecker finally went off the air in December 1989, when the Soviet Union collapsed. It has gone, although more sophisticated over-the-horizon radars are now used by several countries for military and border protection.
Jim VK3PC (SK) 2/7/2016
