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
Alpha Series U Bolt Cushion Clamps, Electro Galvanized - UB11/2PA (Options: 1-1/2" Pipe Size)
Made in USA - Round U-Bolt: Clamping Mount, 5/16-18 UNC, 1″ Thread Length, for 1-1/4″ Pipe, 1.48″ Inside Width, Steel - 08006579 - MSC Industrial Supply