I want to play an older portable radio at camp though my JVC Juke rechargeable speaker the radio is an old Grundig with great reception but not the best sound. I tried to use the head phone jack to the speaker with a 1/8" to 1/8" cord but sounded tremble. The radio also has RCA out jacks. I did some research and found RCAs to 1/8". ( or 3.5mm?) but they are listed for use on an iPod or such to a home stereo and I didn't want to buy another cord to find it don't work either. Anyone know if this would work, or just sound crappy like the headphone jack to the speaker port?