Car radios are more powerful, and of higher quality and price than most common radios sold in consumer electronic stores. Unfortunately, because they are constantly in motion, their reception of radio signals changes. However, there are a few things you can do if you are suffering from poor car radio signal quality.
Check if the antenna is properly attached, if you already own a car with a long, stiff, whip like antenna. You can easily check if the antenna is properly attached by screwing it clockwise, tightly into it's base.
Purchase and install an antenna pre-amplifiers if your current radio equipment is working but too weak to pick up signals. Antenna pre-amplifiers can aid in signal reception by amplifying antenna signals before they reaches the tuner. These device can easily makes weak signals exponentially stronger. Unfortunately, pre-amplifiers are not selective in the noises they chooses to amplify, so specific stations and Radio frequencies will become far more difficult to hone into when there is signal interference.
Purchase and install a diversity tuning system if your current system is operational, but constantly influenced by obstructions. This option allows for better reception by drawing it's signals from two antennas placed on opposing sides of the car. When installed, the car radio tuner will constantly monitor both antennas at the same time and draw from the one that has the strongest signal. This is very useful if you commonly frequent the city where tall buildings can obstruct or incorrectly reflect radio signals.
Clean any paint and corrosion at the site of installation. The chassis of the vehicle provides the ground plane, or electrically conductive surface that airs in the reception of radio signals, for the antenna, so make sure your antenna always has a clear connection to it. After installation has been completed, be sure to coat any exposed metal with grease or silicone glue to prevent rust and corrosion.
If installing a new antenna, be mindful that the location of your antenna on your car is very important in determining the strength of the signals it can receive. The best place to mount a whip antenna is in the center of the roof where glass and metal will not interfere with it's ability to receive the signal. If you have a set of high quality amplifiers in your car keep the antenna away from them as they can cause heavy radio interference.