Adventures of Superman Season 2 Episode 20

Plot hole. Every time the wrecker calls there is a sound of the thump and the bell in the background. When the three transportation executives are gathered in Perry Whites office the call comes in threatening the ship. The wrecker says he will damage the ship at 1:45 PM if his demands are not meant. This gives the staff three hours to give in to the demand. That means the call is being made at 10:45 A.M. No carnival operates in the morning. Also the sound is always there. How is it possible that someone is ALWAYS playing that machine when a call is being made?