Just a personal note to you about WJSV.
Lee Shepard has a web page http://www.lookoutlee.blogspot.com/
He worked at WTOP some years ago. On his web page you can listen
to that WJSV broadcast of 9/21/1939. Go to the site and on the right side under Labels you will find the WJSV broadcast listed.
I enjoy the website and it helps me keep up with what some old friends are doing.