Television Spy (1939)

It's 1939, scientist Douglas Cameron invents a television device called the "Iconoscope". With the Iconoscope television, broadcasts can be send across the country. However, Cameron finds himself pursued by international spies. Eventually the enemy succeeds in stealing the plans. But in the end, Cameron gets them back and even falls in love with Gwen Lawson, the daughter of his former partner and rival Burton Lawson.