"New Stations: Special Land Stations", Radio Service Bulletin, May 1916, page 4. The "7" in 7YS's call sign indicated that the station was located in the 7th Radio Inspection district, and the "Y" signified that it was operating under a "Technical and Training School" license.
"New Stations: Commercial Land Stations", Radio Service Bulletin, April 1, 1922, page 3. Initial Limited Commercial license, serial #585, issued on March 30, 1922, for a three-month period.
