Got this cover recently.
It was sent from the Don Lee Company in San Francisco in June, 1934.

Don Lee made his money souping up Caddys for the rich and famous. In 1919 he branched out into radio broadcasting. At least one of his original radio stations is still broadcasting today.
He then got into television broadcasting. In 1931 he began to broadcast a television signal on an experimental basis for CBS.
He died less than two months after this letter was posted.