A 30-year-old Soviet spy radio has been found by archaeologists in a site cleared for a new lignite mine about 30 km west of Köln in Germany

The spy radio was buried inside a large metal box that was hermetically sealed with a rubber ring and metal screws. Although the radio's batteries had run down after almost 30 years in the ground, the box hissed with inrushing air when it was opened.

The radio has been identified as a model transmitter and receiver — code-named "Strizh," meaning "Swift" — that was manufactured in the Soviet Union in 1987. It was carried by agents into Western Europe shortly after that, and only a few years before the fall between 1989 and 1991 of the "Iron Curtain" of communism that divided Eastern and Western Europe.

The high-frequency or shortwave radio was capable of transmitting and receiving messages as far as 1,200 km — far enough to reach Warsaw in Poland, which was then part of the Soviet bloc.

Media Story - https://www.livescience.com/soviet-spy-radio-discovered-germany.html

More technical details on the R-394KM - https://cryptomuseum.com/spy/r394/index.htm