In this manuscript, an engineering prototype of a proposed mid-frequency radio astronomy antenna array characterization results and system are reported. The mid-frequency aperture array is intended as part of the SKA, envisaged to work between 300 MHz and 1400 MHz. This prototype is a tightly coupled phased array consisting of periodical closely packed elements, known as low-cost printed dipoles. For further indepth studies into the manufacturing processes, construction and development of aperture arrays, a large prototype scale of the array $6 m \times 6 m$ has been constructed such that the beam pattern, and hence the response of the array to radio sources in the sky could be verified. The characterization of the antenna array is based on an artificial flying source beam calibration procedure adapted to verify the accuracy of antenna response. The beam pattern characterization results compared to detailed full-wave simulation are discussed. This work demonstrates the value of the in-situ measurements-simulation approach for the proposed antenna design work.