Extraterrestrial communication signals are hypothesized to be present in an extensive search space. Using principles of communication theory and system design, methods are studied and implemented to reduce the signal search space, while considering intentional transmitter detectability. The design and observational work reported in this paper adds material to previous related reports. (ref. arXiv:2105.03727, arXiv:2106.10168, arXiv:2202.12791, arXiv:2203.10065). In the current work, a two-element radio interferometer telescope and receiver algorithms are utilized to perform differential angle-of-arrival and multi-bandwidth measurements of delta-t delta-f polarized pulse pairs. The system enhances extraterrestrial signal detectability, while reducing signal false positives caused by noise and radio frequency interference. Statistical analysis utilizes a Right Ascension filter spanning celestial coordinate ranges that include the previously determined anomalous celestial direction: 5.25 +- 0.15 hr Right Ascension, -7.6 degrees +- 1 degree Declination. Observations were conducted during a duration of 61 days, comprising 244 hours of interferometer measurements.