that little sony set has no internal antenna for either am or fm. i'd say to try the antenna on your roof and/or get info on how to fab simple antennas.
those two radios you have (Blaupunkt Derby Deluxe and a Grundig Satellit 700) are super fine instruments - both rare these days and collectible. i can see why you don't want to settle for just any old reception with that sony.
cc crane sold a big roll of wire (235.1') years ago; you'd set it behind the radio and enjoy better reception. you might call them and see if they still sell that.
good luck.
Forrest