The PHILCO Phorum

While waiting for my caps to arrive, I have been looking into the FM antenna situation on my radio. I have the "line cord antenna" which connects to pin 2 of the little plug on the chassis back. I have seen pictures of these radios with a very different FM antenna setup, a wire running in a single loop around the very back of the cabinet, but attached to the same pin 2. Having read Philco's instruction sheet for the radio, I see they say it should NOT be externally grounded. Looking at the schematic, I was thinking that using the present "line cord antenna" as a virtual ground, attached to pin 1 of the little plug, and a single loop antenna attached to pin 2 might give good results. Attached are the relevant schematics. Any thoughts ?

Leave the antenna connected to the line cord as is, it works very well. The location on the power cord is located 1/4 wavelength at FM broadcast freqs from the internal line to chassis caps which act as a ground to chassis. Therefore, 1/4 wavelength down the power cord, you are at a relative signal voltage maximum and this is where the capacitive coupling to the antenna input is located.

When operating correctly, the reception with the line antenna is excellent.