I worked at a small, local ISP in the 90:ies that had a point to point link across the river, handling the dial up traffic from the telecom company we partnered with.
Every few days, always at roughly the same time, all incoming dial up traffic would drop. A minute later, the customers could reconnect.
It took a while before we realized that one of the huge passenger ferries that docked a short distance upstream was the cause. When it arrived and departed, its chimneys and possibly bridge and highest deck blocked LOS across the river.
Every few days, always at roughly the same time, all incoming dial up traffic would drop. A minute later, the customers could reconnect.
It took a while before we realized that one of the huge passenger ferries that docked a short distance upstream was the cause. When it arrived and departed, its chimneys and possibly bridge and highest deck blocked LOS across the river.