[Tynwald]

I posted this on FB but knowing that not all of us use social media, it seemed sensible to ask my question here. 

I recently acquired this 630CSX chairside that has an unusual (at least for me) power cord with three wires; two for AC and one for the antenna. There's a place on the plug where a long wire could be attached, presumably to improve SW reception. Has anyone encountered this before? The cord is a complete loss and will need to be replaced. I'm tempted to reuse the funky plug but am unsure how to do it. It may not be obvious from the picture but the plug is flat, so it wouldn't be easy to connect a conventional line cord to it (what's there now almost looks like old 300 ohm feed line). I'm also curious to know if having the antenna line so close to the AC would introduce 60 Hz hum. Maybe the best thing to do is to switch to an era appropriate power cord and plug with a separate line for the antenna, although it would be fun to try reproducing the original. Thoughts?