Plane Wave Generators (PWGs) utilize arrays of radiating elements to approximate plane wavefronts, thereby creating localized far-field-like conditions within a Quiet Zone (QZ). Their compact form factor makes them especially advantageous at low frequencies, such as in the VHF and UHF bands, where traditional Compact Antenna Test Ranges (CATRs) become impractically large. This paper presents results from a comprehensive validation campaign of a 19-element PWG demonstrator, conducted as part of a broader development program aimed at realizing a full-scale system for VHF/UHF testing. The campaign, executed at Pulsaart by AGC, involved both element-level and array-level assessments using a spherical near-field multi-probe system. Key objectives included validating QZ synthesis, calibrating array excitations via digital twin modeling and field expansion methods, and quantifying realized excitation errors. The findings confirm the robustness of the PWG design, the effectiveness of the calibration process, and the minimal impact of mutual coupling and active impedance variations on performance.