Assembly is easy, bottom part has hole on the bottom for support rod, coaxial cable can be inside of hollow rod or there is hole on side to pull out cable outside. Middle part is holding radial wires bent inside of middle part. There is attached outer braid of coaxial cable. Its fixed firmly by top part. Top part holds vertical radiator with coax center wire connected by screw. 

Its designed for support rod diameter 16 mm, vertical wire 6 mm, and radials 4 mm diameter. In case of different dimensions it can be easily adjusted and regenerated in FreeCad.