What car have you got? Many cars nowadays have amplified antennas and the factory head unit supplies power (sometimes up the antenna cable - no extra wires). Without this, the antenna works very poorly - with any head unit, including the empeg.

Cars that have these include the new Civic, all VWs, all BMWs, etc.

It's very unlikely your tuner is defective, the actual gubbins doing the tuning is a sealed module we buy - *very* expensive as a component part and fully adjusted/setup/tweaked by the manufacturer.

Hugo