Popping sounds are from the the ignition - spark plugs, wires and distributor. Most modern cars have "radio resistor plugs" & "spark plug wires" installed from the factory. If unsure on an older car, check under the hood and inspect the wires & plugs.
Make sure your radio AND antenna system are solidy grounded. Poor grounds can allow all kinds of strange sounds and erratic behavior from the radio.
Also, connect the + & - power leads DIRECTLY to the battery. You can pass the + lead through a dedicated relay that opens when the key is removed if you want, but avoid like the plague connecting the + lead to a terminal in the fuse box and the - lead to an arbitrary grounded point on the body. Direct connections to the battery helps to prevent a way for noise to enter the radio on the power leads.
You may also be hearing the electric fuel pump located in the fuel tank on many newer cars. Solving that sound is very difficult.
Answers & Comments
Popping sounds are from the the ignition - spark plugs, wires and distributor. Most modern cars have "radio resistor plugs" & "spark plug wires" installed from the factory. If unsure on an older car, check under the hood and inspect the wires & plugs.
Make sure your radio AND antenna system are solidy grounded. Poor grounds can allow all kinds of strange sounds and erratic behavior from the radio.
Also, connect the + & - power leads DIRECTLY to the battery. You can pass the + lead through a dedicated relay that opens when the key is removed if you want, but avoid like the plague connecting the + lead to a terminal in the fuse box and the - lead to an arbitrary grounded point on the body. Direct connections to the battery helps to prevent a way for noise to enter the radio on the power leads.
You may also be hearing the electric fuel pump located in the fuel tank on many newer cars. Solving that sound is very difficult.
Good luck!