Review on Enhance Your Car's FM Radio Signal with Universal Auto Car Radio FM Antenna Signal Booster - Amplify Signals for Marine Car, Boat, RV & More! by Rodney Harris

I bought this in the hope that I could add a few more HD transmitters to my Kenwood main unit which supports HD radio. The point is, does it work? Yes. Did it make a big difference, no. I went from zero HD stations while sitting in my driveway to two. Unfortunately, these weren't the two I was hoping for. As for improvements to analog FM transmitters. Yes, it helps a little. Medium stations had almost no static electricity, and weak static stations had less static electricity. The strong stations stayed strong. Keep your expectations low and you will be happy.