Hi everyone

I've replaced the Concert radio in my car recently with Sony but radio signal is very bad (if any). When interior light is removed at the back of the roof I've notice some electronic below the antenna. Looks like amp. How does it get powered? Beside the antenna lead no other wire is going to it. It would indicate it gets its power via the antenna. However, Sony does not have this. Is there an adapter to go in line with antenna for after market radios?