Currently, there is a growing demand for new wireless communications services, which require increasingly higher speeds and have a higher user demand. This leads to exploring the electromagnetic spectrum with millimeter waves (mmWaves), which is a complement to this high demand. One of the problems of these spectrum bands for research and teaching is the high cost of measuring equipment, for this reason, in this research the use of signal harmonics for the transmitter under test, to make use of equipment between 2 GHz to 18 GHz, to monitor spectrum in the 26 GHz to 40 GHz band. The third harmonic signal is measured with a Signal Hound digital spectrum analyzer and a down converter LNB, the tests carried out to validate the possibility of teaching and researching mmWaves with the proposed structure.