On the second page of this book of sheet music his group is called "Hank Keene and His Radio Gang" but in other text it's called "Hank Keene and His Connecticut Hill Billies." The somewhat pejorative term "hillbilly" is usually associated with the American South. So it's unusual to see it in commercial print next to the word "Connecticut."
Keene was no Yankee, he wasn't even from New England. He was in Lake Charles, LA. His father Abner Keene (aka Henry Newcomb) was in show biz and relocated often. Hank attended primary school in New York, Illinois, Florida and Kentucky. He graduated from the University of Kentucky High School and then Tufts College in Boston. Thus a native southerner was imported into the deepest darkest Yankee hinterlands.
Connecticut Hill Billies in 1930. His parents by then had bought an already famous home in Southern Coventry in Connecticut The Nathan Howard House. After he graduated from Tufts he got his own radio program on WTIC. His Hillbillies cut their first sides for Brunswick in February of 1931. They cut another 15 sides for Bluebell and Banner before the end of 1935.
The book Pickin' on Peachtree by Wayne W. Daniel has Hank Keene on WSB-AM in Atlanta in April of 1931. It's probably true. The book Yankee Twang by Clifford Murphy puts Keene on radio stations in new York, Cleveland, Wheeling, and Louisville. I've confirmed WHAS and no others except strangely 1400 WRDO-AM in Maine circa 1936. But by 1933 Hank was firing up his own traveling tent show.
His tent show rolled around the country for at least 10 years selling his books of sheet music everywhere they went. His earliest was printed in 1932! By 1946 he was host of a "coast-to-coast program" sponsored by Velvet Tobacco. Billboard noted that he was part of the SESAC Transcribed Library Service, recording programs to be shipped off to 200 radio stations for syndication. that was October. His father Abner died the following year and Keene vanished from the trade magazines.