  Discoverable interstellar communication signals are expected to exhibit al
least one signal characteristic clearly distinct from random noise. A
hypothesis is proposed that radio telescope received signals may contain
transmitted delta-t delta-f opposite circular polarized pulse pairs, conveying
a combination of information content and discovery methods, including symbol
repetition. Hypothetical signals are experimentally measured using a 26 foot
diameter radio telescope, a chosen matched filter receiver, and machine post
processing system. Measurements are expected to present likelihoods explained
by an Additive White Gaussian Noise model, augmented to reduce radio frequency
interference. In addition, measurements are expected to present no significant
differences across a population of Right Ascension ranges, during long duration
experiments. The hypothesis and experimental methods described in this paper
are based on multiple radio telescope delta-t delta-f polarized pulse pair
experiments previously reported. (ref. arXiv:2105.03727, arXiv:2106.10168). In
the current work, a Right Ascension filter spans twenty-one 0.3 hour Right
Ascension bins over a 0 to 6.3 hr range, during a 143 day experiment. Apparent
symbol repetition is measured and analyzed. The 5.25 plus or minus 0.15 hr
Right Ascension, -7.6 degree plus or minus 1 degree Declination celestial
direction has been associated with anomalous observations in previous work, and
continues to present anomalies, having unknown cause.
