Extra exam question E4E11

WhyLocal AM broadcast signals can combine to generate spurious signals on the MF or HF bands when nearby corroded metal connections act as unintentional mixers and reradiate the result. Local AM broadcast signals can combine to create spurious mixing products on the MF or HF bands when nearby corroded metal connections, rusty fasteners, gutters, fences, or similar loose metal-to-metal joints, act as unintentional nonlinear mixers, picking up the strong broadcast signals and reradiating intermodulation products, answer B. Overmodulation by the broadcast station, receiving skywave signals, and receiver IF overload are all different phenomena that don't explain this specific rusty-bolt mixing effect.