I never built it, but I have a few thoughts lol...........
You said a few of the wires are long, so you surely want to shorten them up.
Placing a cap or an RC in the circuit probably will work.
Filters can roll off the frequencies you don't want to amplify, so maybe adding a cap from signal IN to ground may work.
capacitor = 1/(2 * PI * resistor * frequency Hz) = roll-off frequency
Is the station AM? AM usually bleeds over any type electronics that is close by, there is several ways to fix that.
good luck.