QSL R120RT

QSL card from special callsign R120RT, commemorating the 120th annivesary of the experiments by radio pioneer Alexander Popov (Александр Степанович Попов, 1859-1905). In 1895 Popov invented a coherer-based radio receiver to detect lightning stikes. Shortly afterwards, after the release of Marconi wireless patents, he developed radio telegraphy applications in Russia.