In 1920, the Marconi Wireless Telegraph Company of America sold the Chatham and Marion stations to the Radio Corporation of America. RCA removed all remaining Marconi equipment from the Chatham receiver station and converted it to a public coast station for communications with ships at sea. In 1921 Chatham was licensed under the callsign WCC for communications on 500 kHz, 750 kHz and 1 MHz. In 1922 RCA moved the WCC radio transmitters to the Marion transmitter station to eliminate co-site interference to the sensitive receivers at Chatham. In 1929 WCC Marion began operations on maritime HF frequencies (6, 8, 12, 16 and 22 MHz).
