Amazon.com: U-Bolt Pipe Clamp U Bolt Assembly For Outdoor Antenna,secure an antenna mast (as well as pipes and ropes) of up to 1 5/8” diameter 2pcs : Electronics
Single Clamp-On U-Bracket Sets - Sign Mounting Hardware | TAPCO
Hardware Essentials 1/4 in. x 1-3/4 in. x 1 in. Stainless Steel U-Bolt with Plate and Hex Nuts (5-Pack) 320872 - The Home Depot
B-Line B441-22AZN U-Bolt Beam Clamp, For Use With: 13/16 to 15/8 in High Channel, Specifications: 150 in-lb Torque, Channel Mount, Right Angle Under Flange Channel Position, 3/4 in THK Flange, 1200 lb