What is the iron tower on the top of Wanghailou Mountain used for?

Are you talking about Wanghai Tower in Zhuhai? That is the Zhuhai Radio and Television Transmission Tower on Shijing Mountain, which should be used to send analog TV signals. Information shows: The main tower of Shijingshan TV Tower is 180 meters high and has a steel structure. The tower weighs approximately 610 tons.

As shown in the picture, the towering tower in the center is the main tower of the TV Tower. (The short tower on the left looks like some kind of microwave transmission tower used for special communications)

Data map: TV tower on Shijing Mountain