AM Radio noise?
 

I have been getting a very loud whining/werring sound lately on AM radio with my truck and cant seem to track it down. I have cleaned all the ground wire terminals in the engine bay and around the amps and cannot make it any better? It only does it for the first 15 minutes of running time then it clears up, this is also the time the engine reaches operating temp (diesel). The noise doesnt change with engine rpm but seems to fluctuate from high to low. Can this be a antenna fault, or is it more likely to be a ground issue? I definitely seems to be getting worse as time goes on and it started when I changed out the factory head unit with a eclipse HU then when I put the alpine one in it didn't get any better. System includes 9861/h700 and JL amps if that makes any difference? TIA

people still listen to AM radio ??:cheeky4:




switching power supplies are known to interfere with AM reception.. and especially switch mode amplifiers...

If you have a class D amplifier it could be the culprit, otherwise it could be caused by any number of other devices you may have in your truck.......

I know AM sucks but so does sitting in traffic and the AM traffic radio helps find out about hot spots to avoid, so I like to listen to it for the first few minutes of the commute.
Hey I think you may be on to something...... now that you mentioned it, I did change out my sub amp to a JL 1000/1 and that's a D class amp. Is there anything I can do to help stop this (short of not listening to AM, LOL)

try disconnecting the remote turn on and see if the noise persists... bout all you can do is start eliminating any possible noise sources one by one....

Ok, I think the culprit is the antenna but what do you guys think?
I removed the amps from the system one by one and the sub amp definitely made more noise than the three others but there was always a certain amount of squealing/whining weather the engine was running or not. Then while standing near the antenna I noticed it got a little better and when I grabbed it it cleared totally? So I took it of and cleaned the threads and reattached it but it made no difference when I let go. Now don't tell me I have to hang on to the antenna while driving :stroke:
I thought these antennas were just hunks of wire... do they go bad or are some better than others? Why would this noise clear up after about 10 minutes of play time? One other thing is not all the am stations are as bad as the others but as a stroke of luck the one I want to listen to is the worst :mad:

Change the ant first......................