Terahertz (THz) time-domain holographic detection unit prototype for studying propagation dynamics of broadband vortex beams carrying optical angular momentum was developed. The setup consists of a femtosecond laser system, a THz radiation generator, a replaceable set of modulation components for shaping various OAM-beams, an optical delay line, and a wide-aperture electro-optical detecting module with 3D-printed mechanical parts. 3D-printed kinematic mounts of designed detection unit are available for public use as open-source hardware.