  The specifications of the Atacama Large Millimeter Array (ALMA) have placed
stringent requirements on the mechanical performance of its antennas. As part
of the evaluation process of the VertexRSI and Alcatel EIE Consortium (AEC)
ALMA prototype antennas, measurements of the path length, thermal, and azimuth
bearing performance were made under a variety of weather conditions and
observing modes. The results of mechanical measurements, reported here, are
compared to the antenna specifications.
