Metal shields can be used to block noise entering the antenna. The attached photos from the Geesthacht fish ladder near Hamburg show a U shaped metal that surrounds the antenna on both sides, only allowing the field in the center of the loop.
It's important that the metal shield does not encircle the loop or current will flow around the shield. The Geesthacht shields work because they are only on two sides.
Warren Leach
Metal shields can be used to block noise entering the antenna. The attached photos from the Geesthacht fish ladder near Hamburg show a U shaped metal that surrounds the antenna on both sides, only allowing the field in the center of the loop.
It's important that the metal shield does not encircle the loop or current will flow around the shield. The Geesthacht shields work because they are only on two sides.