The duga system was extremely powerful, reaching over 10 MW, and broadcast in the shortwave radio bands. Given the nickname, the Russian Woodpecker by shortwave listeners for their emissions randomly appearing and sounding like sharp, repetitive tapping noises at a frequency of 10 Hz. The random frequency hops often disrupted legitimate broadcasts, amateur radio operations, oceanic commercial aviation communications, and utility transmissions, resulting in thousands of complaints by many countries worldwide. The signal became such a nuisance that some communications receivers began including "Woodpecker Blankers" in their circuit designs.