Jolly Jack Robel and his Radio Band, that's the artist name on the Vocalion 78 I have here. He sang, conducted, played clarinet, bass, violin and harmonica and had his own 12-piece orchestra. He had a radio program on 1490 WAZL-AM in Hazleton, and another on WPAM-AM. Jack also sold some of his songs to the Andrews sisters. One of these was the infamous "Beer Barrel Polka." Jack Robel was a polka pioneer if you will. he was one of several Polka artists that pushed polka toward a more popular and less ethnic audience. his works favored dance rhythms, and full orchestras like more common pop music of the era. It was a more homogeneous and a new and truly American style of polka. This makes sense when you realize that while was born in Ukraine, he learned clarinet from a Tommy Dorsey an American swing legend. Some sources credit him with writing the "Beer Barrel Polka" in 1936. For that he will never be forgiven.
But it was a different time and place. The coal mines of the Shenandoah were cracking and Polish and other western European immigrants worked the mines. Local stations like 1450 WPAM-AM, 1530 WMBT-AM and WMIM-AM all ran polish programming regularly to serve that audience.
In the beginning Jolly Jack put together a band of Slovak musicians and started playing the ethnic polish programs on WAZL-AM and WEEM-AM. WAZL and WPAM eventually gave him his own program. Then he moved on to playing ballrooms back when that was a way to reach people. In a small burg like Pottstown a big show might draw 1000 people. It was gigs like that which got his band recorded in New York and sides released on Brunswick, Vocalion, Columbia and at least 40 LPs for Decca. More here.
WAZL is still an ethnic station today, now serving the growing Hispanic population. I do recommend you read the Fybush tour of the Pennsylvania coal country radio stations here. Almost all these stations appear in his essay.