After moving to Denver, Reynolds joined with other radio enthusiasts in making a number of "mobile" demonstrations, where radio-receiver equipped automobiles picked up special programs. He participated in the May 19, 1921 broadcast of the opera "Martha" from the Denver Municipal Auditorium. In the summer of 1921, Reynolds was issued a "Special Amateur" license, with the call sign 9ZAF. This allowed transmissions on 370 meters (811 kHz), a wavelength with less interference than 9JE had encountered on the congested standard amateur wavelength of 200 meters (1500 kHz). In addition to experimental broadcasts, 9ZAF acted as a "relay station" for coast-to-coast messages passing through a cooperative network of Amateur Radio Relay League stations. In October, it was announced that 9ZAF's equipment had been upgraded, and, in addition to Sunday evening concerts from 8:00 to 9:30 p.m., the station was broadcasting daily weather forecasts twice a day, at 8:30 a.m. and 9:00 p.m. In early 1922, the "Rocky Mountain News" announced it was providing news bulletins as a supplement to the nightly station concerts. The paper also started promoting 9ZAF, referring to the station as the "News-Times-Reynolds Broadcasting station".