Latest discoveries in the field of astronomy have been associated to the development of extremely sophisticated instruments. With regards to radio-astronomy, instrumentation has evolved to higher processing data rates and a continuous performance improvement, in the analog and digital domain. Developing, maintaining, and using such kinds of instruments - especially in radio-astronomy - requires understanding complex processes which involve plenty of subtle details. The above has inspired the engineering and astronomical communities to design low-cost instruments, which can be easily replicated by the non-specialist or highly skilled personnel who possess a basic technical background. The final goal of this work is to provide the means to build an affordable tool for teaching radiometry sciences. In order to take a step further this way, a design of a basic interferometer (two elements) is here below introduced, intended to turn into a handy tool for learning the basic principles behind the interferometry technique and radiometry sciences. One of the pedagogical experiences using this tool will be the measurement of the sun's angular diameter. Using these two Ku band receptors, we aim to capture the solar radiation in the 11-12GHz frequency range, the power variations at the earth spin, with a proper phase-lock of the receptors will generate a cross-correlation power oscillation where we can obtain an approximation of the angular sun's diameter. Variables of interest in this calculation are the declination of the sun (which depends on the capture date and location) and the relation between maximal and minimal power within a fringe cycle.