Russian Woodpecker

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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, repetitive 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. Simple CW pulses didn't appear to have any effect however playing back recordings of the woodpecker transmissions sometimes caused the woodpecker transmissions to shift frequency leading to speculation that the receiving stations were able to differentiate between the "signature" waveform of the woodpecker transmissions and a simple pulsed carrier.

In 1988, the Federal Communications Commission conducted a study on the Woodpecker signal. Data analysis showed an inter-pulse period 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 signal 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. One of the sites is located within the 30 mile Zone of Alienation around the Chernobyl power plant - it was most likely shut down and abandoned after the disaster in 1986.

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.

Transmission power on some woodpecker transmitters was estimated to be as high as 10 megawatts. As well as disrupting shortwave amateur radio and broadcasting it could sometimes be heard over telephone circuits due to the strength of the signals.

Contents 1 Triangulated Positions of Transmission Sites 2 Alternative theories as to the purpose of the Woodpecker transmissions 3 Electromagnetic and Spectrum Compatibility (1989-Present) 4 References and further reading 5 External links

[edit] 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

[edit] Alternative theories as to the purpose of the Woodpecker transmissions

The theory that the Woodpecker transmissions were for an over the horizon radar system was widely but not universally accepted. Among the alternative theories put forward as to the purpose of the transmissions included broadcast jamming, submarine communications and even an attempt at mass subconcious mind control. After the fall of the Iron curtain it was possible to verify that the woodpecker was indeed a military radar system. The broadcast jamming theory was debunked early on when a monitoring survey showed that Radio Moscow and other pro-Soviet stations were just as badly affected by woodpecker interference as Western stations.

[edit] 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 negotiations 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 near Chernobyl, 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.

[edit] References and further reading

• Headrick, James M., "Looking over the horizon," IEEE Spectrum, pp. 36 - 39 (July 1990).
• Headrick, James M. and Skolnik, Merrill I., "Over-the-horizon radar in the HF band," Proceedings of the IEEE, vol. 62, no. 6 pp. 664 - 673 (June 1974).
• Headrick, James M., Ch. 24: "HF over-the-horizon radar," in: Radar Handbook, 2nd ed., Merrill I. Skolnik, ed. [New York: McGraw-Hill, 1990].
• Kosolov, A. A., ed. Fundamentals of Over-the-Horizon Radar (translated by W. F. Barton) [ Norton, Mass.: Artech House, 1987].
• Martinez, J.P., G3PLX, Letter to Editor: "Woodpecker," Wireless World, p. 89 (April 1982). Available on-line at: http://dspace.dial.pipex.com/brogers/Wpecker6.htm
• Wilson, David L., "The Russian Woodpecker...A Closer Look," Monitoring Times, pp. (?) (Summer 1985). Available on-line at: http://dspace.dial.pipex.com/brogers/Wpecker5.htm
• (?), "Mystery Soviet over-the-horizon tests," Wireless World, pp. 53 (February 1977). Available on-line at: http://dspace.dial.pipex.com/brogers/Wpecker2.htm

[edit] External links

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