When was the modern radio invented?

Generally in the 20th century (1900-1999), because there were so many different kinds, including AM, FM, satellite, digital, tube (valve), transistor, integrated circuit, boombox, walkman, shortwave, AC/DC, hi-fi, stereo, quadraphonic, SCA (muzak), HDradio, digital radio mondiale, SDR (software defined radio), superheterodyne, walkie-talkie, cellular, etc.