This prototype is a low-cost, open-source antenna measurement system based on Software-Defined Radio (SDR) and Raspberry Pi devices. It enables automated azimuthal and elevational rotation of an antenna using a stepper motor, and features synchronized signal data acquisition via the bladeRF platform. Signal processing and post-processing techniques are integrated to enhance the accuracy of power measurements. Real-time visualization of antenna radiation patterns is provided in both rectangular and polar formats through a dedicated graphical user interface (GUI). The system’s performance has been validated through the characterization of a flexible ultra-wideband antenna operating in the 700 to 6000 MHz frequency range, demonstrating an acceptable level of measurement accuracy. This prototype offers a scalable and flexible solution with valuable capabilities for antenna design validation in both academic research and applied telecommunications contexts.