E4E11 (B) 
What is the most likely cause if you are hearing combinations of local AM broadcast signals inside one or more of the MF or HF ham bands? 
A. The broadcast station is transmitting an over-modulated signal
B. Nearby corroded metal joints are mixing and re-radiating the BC signals
C. You are receiving sky-wave signals from a distant station 
D. Your station receiver IF amplifier stage is defective
