April 2002 Report, paragraph 1 of section 5 of the ASAC Report:

The ASAC heard detailed reports both on the progress of the prototype
antennae under construction as well as on the plans for their testing
in Socorro, NM.  In particular, it was gratifying to hear
that the North American antenna is expected to be assembled and ready
for testing this summer. The program for evaluation of antenna performance
seems satisfactory although it is regrettable that interferometric
holography will probably not be possible in practice. The ASAC is
worried by the tight schedule for testing the European and Japanese
prototypes which are each scheduled to arrive in Socorro in April
2003. It seems extremely important that the delivery schedule be
adhered to in order to allow testing for all three prototypes to be
concluded by the end of 2003. The ASAC would also like to underline the
importance to the project of the choice of a single antenna design
subsequent to an objective comparison of all three prototypes. This
presumably would allow cost savings and increase ease of maintenance
which, in the end, will increase the productivity of ALMA. The ASAC
also notes that the choice of a single antenna type is particularly
required to guarantee good performance for polarization measurements.