Russian Woodpecker

The Russian Woodpecker was a notorious Soviet signal that could be heard on the shortwave radio bands worldwide between July 1976 and December 1989. It sounded like a sharp tapping noise, at 10 Hz, giving rise to the "Woodpecker" name. The random frequency hops disrupted legitimate broadcast, amateur radio, and utility transmissions and resulted in thousands of complaints by many countries worldwide.

The interference dogged amateur radio operators worldwide and led to a thriving industry of "Woodpecker filters" and noise blankers. One idea amateur radio operators floated to combat this interference was to attempt to "jam" the signal by transmitting synchronized unmodulated continuous wave signals, at the same pulse rate as the offending signal. This idea was considered, but abandoned as impractical.

In 1988, the Federal Communications Commission conducted a study on the Woodpecker signal. Data analysis showed a pulse repetition frequency of about 90 ms, a frequency range of 7 to 19 MHz, a bandwidth of 0.02 to 0.8 MHz, and typical transmission time of 7 minutes. The radar was observed using three repetition rates: 10 Hz, 16 Hz and 20 Hz. The most common rate was 10 Hz, while the 16 Hz and 20 Hz modes were rather rare. The pulses transmitted by the woodpecker had a wide bandwidth, typically 40 kHz.

The Woodpecker turned out to be an over-the-horizon radar system known to NATO as Steel Yard. The first operational site was located near Gomel in what is now Belarus, and the second site was at Komsomolsk-on-Amur in Siberia.

The use of the shortwave spectrum, which was sensitive to ionospheric refraction, allowed the Soviets to detect alterations in ionosphere propagation caused by the depletion of ions by missile exhaust plumes.

Triangulated Positions of Transmission Sites

• Gomel PPL 55°19'00"N 028°47'00"E
• Gomel PPLA 52°26'30"N 030°59'00"E
• Gomel-Gorod ADM2 52°26'30"N 030°59'00"E
• Gomelskiy Rayon ADM2 52°20'00"N 031°00'00"E
• Pokolyubichi AIRF 52°31'32"N 031°00'49"E
• Severnyy RSTN 52°27'00"N 030°58'00"E
• Stantsiya RSTN 52°26'00"N 031°00'00"E
• Chernobyl PPL 51°16'00"N 030°14'00"E (fully deactivated?)

Electromagnetic and Spectrum Compatibility (1989-Present)

By the mid-1990s at least the two radars located in Ukraine appeared to have been deactivated, since their continued maintenance did not figure in the negotations between Russia and Ukraine over the active early warning radars at Mukachevo and Sevastopol.

Another over-the-horizon radar of this type was built at Komsomolsk-na-Amure. Along with the facility at Kiev, the other Steel Yard located at Komsomolsk-na-Amure provided complementary coverage of the United States.

According to some reports, the Komsomolsk-na-Amure installation was taken off combat alert duty in November 1989, and some of its equipment was subsequently scrapped.

References

• The Russian Woodpecker, Miami Herald, July 1982.
• Steel Yard OTH, globalsecurity.org.