Mil. Ground Plane Antenna 3 Radial Cast Aluminum Head with Mobile Ball Joint  with standard whip antenna 3/8”-24 hole for mounting. Fits into a Gray-4 1.25“Dia Mast pipe. Takes ½” Radials per your design. Female  UHF Connector.  It’s Approx 6” Tall and the same Dia. Wt 3 lbs.