"...an area of a few blocks flooded with war surplus equipment, the overflow from the dusty boxes spilling out onto the sidewalk in bulging cardboard boxes. Hobbyists would scrounge the boxes brimming and bulging with old tubes, dials, transformers, and equipment with serious looking faceplates, mysterious dials, and toggle switches."The famous New York radio row wasn't the only one. There was another in Chicago which was home to WBKB-TV and the Chicago Radio Club and a Naval radio School. That sprung up in about 1940. The image below is from a Billboard article in 1945 centered around the clustering of KUTA-AM, KUTA-FM, KDYL-AM, KSL-AM and KLO-AM. But there was another in Hollywood, CA. It was centered around the KECA Playhouse on North Highland Avenue at the intersection of Sunset Boulevard. Programs for both KECA-TV and 790 KECA-AM were produced there. the building was formerly known as the Hollywood Playhouse and was operated independently by Earl C. Anthony.
The words "radio row" came into use quickly I found usage in 1922 and 1924 in some sales literature. The New York Times made an early reference to "Radio Row" in 1927. In 1929 The magazine Popular Mechanics was using it. By 1930 the New York Commissioner of Health was using the term "radio row" complaining about the noise on Radio Row from loudspeakers.