Russians celebrate the 7th day of May as their radio day. On May 7, 1895, a Russian navy officer Alexander Popov presented his lightening detector to the Russian Physical and Chemical Society. His device was a radio receiver capable of detecting electromagnetic waves coming from lightening. Thus to Russians, Popov is the inventor of radio communication. 

Popov's work as a teacher at a Russian naval school led him to explore high frequency electrical phenomena. On May 7, 1895 he presented a paper on a wireless lightning detector he had built that worked via using a coherer to detect radio noise from lightning strikes. In a March 24, 1896 demonstration, he used radio waves to transmit a message between different campus buildings in St. Petersburg.

His work was based on the work of other physicist - Oliver Lodge, and contemporaneous with the work of Guglielmo Marconi. Marconi had just registered a patent with desciption of the device two months after first transmission or radio signal made by Popov.

According to wikipedia