1999 Mercedes CLK radio antenna

FM need a good antenna, buT FM in the country side will be weak
or even dead, FM does not travel far at all ,even only 20 miles
AM we have super power stations that cover most the country.
I bet the RADIO is just fine.
it can be bench tested with a 1 strand of say 4 feet of wire for an antenna.
you posted about only a RADIO not CD and not AM
FM is short ranged, 88 to 108MHz. is that
no town told , but you can call your closest station and ask them there coverage, spec.? 50miles or 10 or? what ever.
or you can go to a 2nd car, test FM see if there is one strong station.
if not there there is none.
on home RADIO we use a roof mounted 30Ft high antenna, FM
and goes way father,.
in car that can not be done, most antenna amps in cars only increase noise.
is this your first car, or first ever FM radio.?
yes antenna's can fail even the ground, (it is 2 wire coax to fail)
the mount can corrode. the cable can be bad.
some have antenna in the wind shield glass, and some one puts in new glass with no antenna there well that fails hard.
FM is mostly a CITY BIG DEAL, no living in the sticks.
also there are tiny FM micro station,and those are weak.
only line get a FM map for you town, just like Cell phones but for FM.
radio. see what is there and its POWER/coverage.

Most likely the antenna lead has come unhooked from the back of the radio. AM stations will pick up with the internal working of the radio, but FM stations have to have a working antenna to work. Also make the antenna is tight to the vehicle .

The alternator is most likly the problem. If it was ok before and you had the alternator replaced the problem should be the new alternator. The above answer is if static is your problem. If you can not pick up stations there is a good chance that you have a antenna problem.

check your antenna

If you pick up FM. It isn't the antenna. It's an internal radio problem.

Make sure the antennna is still there and not missing, if thats ok then remove the radio and make sure the antenna is plugged into the rear of the radio,

antena wire

YOU MAY HAVE A PROBLEM WITH THE ANTENNA. THERE ARE 4 ANTENNAS IN THE REAR WINDOW FOR BOTH AM AND FM SIGNALS. THERE IS AND UNIT CALLED A DIVERSITY BOX UNDER THE REAR HAT SHELF THE CONNECTS THEM ALL AND DECIDES WHAT ANTENNA IS GETTING THE BEST SIGNAL. THAT UNIT MAY BE FAULTY. BEST TO HAVE IT CHECKED BY SOMEONE WHO KNOWS THE SYSTEM OR TAKE IT TO A DEALER. MIGHT BE CHEAPER THAN BUYING A NEW AFTERMARKET RADIO.

I’m happy to help further over the phone at https://www.6ya.com/expert/anthony_dda4e0152e94f3c0

this usually is caused by either a defective antenna ground to the chassis of the car or a defective antenna or antenna lead to radio.

check radio antenna. could be loose connection or antenna missing or broken.