This paper describes the design, construction and test of a 129-174GHz multi-pixel heterodyne receiver suitable for radio astronomical observations and for IRAM's 30-m telescope at Pico Veleta. The design of broadband microwave components like LO injection coupler, corrugated horn, mixer, is discussed, including FDTD simulations, and the performances of those components tested with IRAM-designed HP8510 millimetre extensions are presented. The quasi-optical scheme of the receiver, designed to interface with the 30-m telescope optics, is presented in details. The overall receiver operation, especially the cryogenic part, and it performances in terms of noise temperature are presented. In conclusion, some observations of molecular transitions in astronomical sources made with the 129-174GHz prototype are shown.