My 98 C5 convertable has a great FM and and a terrible AM radio. FM and CD sound GREAT. AM has static and other noise on all but strongest AM stations. Have a 50KW AM transmitter about 2 miles away. OK on this one but marginal on others. Are there 2 seperate antennas in the convertable like in the coupe? Do I have a mixing box located somewhere near the rear quarter panel or do I just have a terrible AM radio?

 

Hey it must be a common problem i have the same problem with my 97,
sometimes even fm is not that good,wish i could help

 

When I was a junior engineer with Houston Light and Power in the 1970s, company cars came with AM-only radios (an extra-cost option, back then) not so we could listen to the radio but so we could drive around with them on all the time, listening for static and hum - a sure sign some power equipment near by had poor connections.

AM reception can often be tricky even with a strong signal nearby because the receivers can and do pick up all sorts of nearby signals and relfections of the signal they are trying to track, making a mess -- the bottom line is that it does not work as well as FM and that some receivers just don't do well with it at all. Most people today forget (or don't know) that the whole reason FM was invented and became so popular was that AM was so difficult to tune properly, and still got lousy reception anyway.

If your FM reception is good, then there is probably nothing wrong with the car's receiver. You can check the integrity of the antenna lead from the antenna to the radio amp, but it is probably ok.

 

GM Service Manual says to check for poor grounds. Will do that but dont think that is the problem. This AM radio really is worse than one I had in my 50 chevy. Amplifiers are FINE but AM receiver either has poor SN ratio or has some problems.