On December 3, 1936 WQXR became the first licensed high fidelity broadcaster in the U.S. after changing its call letters from W2XR. 

W2XR went on the air March 26, 1929 as an experimental mechanical television station owned by radio engineer John V.L. Hogan. In June 1934 the license was renewed and it became the first experimental high fidelity station in the country, operating at 1550 kilocycles and 250 watts. W2XR operated several hours a day as a sound accompaniment to television pictures with which Hogan was experimenting.  Listeners could not receive Hogan's telecasts, but they could hear the high fidelity classical recordings he used as background and flooded his office with letters asking for more.

In February 1936, Hogan and Elliott M. Sanger formed the Interstate Broadcasting Company and applied to the FCC to transfer W2XR's ownership and increase power. On May 21st of that year W2XR's license was transferred to the newly formed company. Spring also brought with it an increase in power to 1,000 watts, their first paying sponsor--Martinson's Coffee--and a move to new studios at 730 Fifth Avenue. In June 1936 the first program guide was issued. -- WNYC & WQXR Archives

Slide Show: A Visual History of WQXR