I have a small portable FM receiver on which I listen to radio sometimes. I have it kept on top of my fridge. Today morning, I noticed a strange thing happening: When I opened the door of the fridge, the volume went really low. And when I closed it again, the volume went up. I did it 4-5 times.. and this thing happened every time. When the door is partially closed the sound is louder than when the door is completely opened. I might bee seeing things here.. but it was something like an exponential. When the door was near to getting opened completely, the volume drop was high. What could have been causing this? The body of the fridge is metallic.. does that have to do something with this?