Internal radio antenna
 

I don't know if anyone has posted something like this here before, but I know some people would like to get rid of their external antenna but still have radio reception. I saw this in an email from Jegs:

Mr. Gasket 6100 Mr. Gasket Hidden Radio Antenna

I simply relocated the existing radio antenna to inside the car. I noticed a reduction in reception when I'm downtown or >50 mi from the city, but I find it perfectly acceptable. If you're not at the edge of reception for your favorite station, I recommend relocating your antenna to inside the cabin.

Automotive antennas use the metal body of the car as part of the antenna, there are many types of antennas so you might notice that the hidden antenna does not look like the whip that you are used to, to get good reception an antenna tends to have two parts or two wires because they are picking up an electrical signal from the air.

No, that's not how it works.

A car's audio system is completely isolated from the chassis, that's why each speaker has two wires from the stereo rather than using ground. And any antenna I've seen is just one wire.