An Interference-Resistant Search for
Extraterrestrial Microwave Beacons


Darren Laney Leigh

Submitted to The Division of Engineering and Applied Sciences
on May 21, 1998, in partial fulfillment of the
requirements for the degree of
Doctor of Philosophy


The Billion-channel ExtraTerrestrial Assay (BETA) is a radioastronomical search for
microwave beacons from intelligent civilizations. It searches the 1400-1720 MHz "wa-
terhole" region with 0.5 Hz resolution for narrow-band carriers. BETA incorporates
several systems for terrestrial radio frequency interference mitigation: a terrestrial
"veto" feed, two sky feeds to detect sidereal motion, and adaptive filtering to re-
duce intermittent interference. The search has surveyed the entire sky from +60 deg. to
-30 deg. decliniation twice and is starting a third. During this time it has sifted through
~ 1016 frequqncy bins, followed by ~ 109 candidate features and archived 3500 of these
which passed preliminary tests. No candidate has repeated or otherwise presents the
assumed characteristics of an extraterrestrial intelligent origin.

Thesis Supervisor: Paul Horowitz
Title: Professor of Physics


thesislt.pdf (1.55 MB) ("lite": all, except "picture gallery" [Appendix H])
apph.pdf (615 KB) (hardware picture gallery -- highly compressed)