As of May 1920 the Bureau's Radio Laboratory was reported to be conducting weekly Friday evening concerts from 8:30 to 11:00, transmitting on 600 kHz."13  The Transmission of Music by Radio" by S. W. Stratton, Technical News Bulletin no. 38, Bureau of Standards, June 4, 1920, pages 8-9. That same month, the Bureau demonstrated a portable radio receiver, called the "portaphone", which was said to be capable of receiving broadcast programs up to away. A newspaper article the following August reported that the weekly concerts could be heard up to from Washington. It also noted that "The bureau has been experimenting with the wireless music for several months, and has reached such an advanced stage of development that further investigation to them is useless, and they are going to discontinue the concerts.""'Picking' Tunes From Air Nightly Pastime With Wireless Amateurs", Washington Times, August 8, 1920, page 26. However, the station continued to make occasional broadcasts, and in January 1921 a new distance record was announced when a listener in Chattanooga, Tennessee reported hearing the "jazzy waves whirling out from the Bureau of Standards"."Hear D.C. Radio Music in Tenn.", Washington Times, January 17, 1921, page 1.
