Hi Broubin,
Yes, a sheet of copper will act as a shield, so will aluminum or even mild steel, but not stainless steel. It will have to be grounded in order to drain any rfi/emi though. Before trying that, be sure that your tuner's power cord and antenna lead are nowhere near the cd player's power cord. I had the same problem with a cdp a couple of years ago and simply repositioning the coaxial cable solved the problem.
Yes, a sheet of copper will act as a shield, so will aluminum or even mild steel, but not stainless steel. It will have to be grounded in order to drain any rfi/emi though. Before trying that, be sure that your tuner's power cord and antenna lead are nowhere near the cd player's power cord. I had the same problem with a cdp a couple of years ago and simply repositioning the coaxial cable solved the problem.