Radio issues

[Batesy]

I recently purchased a stock AM radio for my 75 Dart. Installed and it works fine except that when I accelerate the signal gets louder. Idle and especially reverse, the sound level drops. To be extra clear, when I am idle or reverse it's one sound level and then when I accelerate it gets louder and stays at the volume level no matter if I slow down or speed up. Just at idle and reverse does the sound drop a little.
While I am mentioning that, a second problem is that I have the Redirad system hooked up and it works fine too except that it has acceleration noise. Now, I have the power connected to a 20amp fuse which it shares with my tachometer. I am thinking that the tac is transferring the sound. I may need to move the power cable for the Redirad to somewhere else.
Perhaps someone has had a similar problem and can offer some advise. Thanks

 

[67Dart273]

Not familiar with the specifics of Redirad, but the first thing I'd try is to unplug it, and hook the AM antenna up directly

Does this increase in volume come with popping or static?

Might be a bad connection in the antenna / cable

 

[Batesy]

Not familiar with the specifics of Redirad, but the first thing I'd try is to unplug it, and hook the AM antenna up directly

Does this increase in volume come with popping or static?

Might be a bad connection in the antenna / cable

No. It just raises and then is stable until I am completely idle or in reverse.

 

[coffeedart67]

Don't have an answer but I have the same thing with the underdash 8 trackI put in my Dart, it gets louder off of idle.

 

[RedFish]

If radio get louder with engine rpm, weak charging system is the most likely cause.