[Chuck Schwark]

This aerial system is a dipole with a matching transformer to a twited-pair (balanced) lead-in to help eliminate local noise pickup. See my site: http://www.philcorepairbench.com/mystery/40-6112.htm

The "Foreign Tuning System" is an antenna switching arrangement (part of the bandswitch) for selecting either a balanced feed (SW, All-Wave) and unbalanced (local BCB), depending on which band was selected on the radio.

With the Philco High-Efficiency Aerial in place, SW bands enjoyed less noise pickup (due to balanced lead-in). In BC mode the antenna looks like a longwire for local pickup. Today, there is more ambient and household electrical noise than in 1937-38, so an un-shielded twisted-pair lead-in used today would not totally "cure" interference pickup by the antenna system. Back then only motors and "electrical machinery" and an occasional passing streetcar were the major sources of noise.