On 28 August, Kellerman wrote:

 Ravi Subrahmanyan, here at the ATNF, whom I think you all know, has been
looking into cross-talk problems at the AT.  I know we ran into
problems in our vla deep surveys at large hour angles.  The AT problem
is apparently caused by the gaps between the panels, which can be fixed
with taping the gaps; my recollection is that the VLA problem was due to
direct line of sight of one feed seeing another (lo?).  This could be
exacerbated in the e-config.

Darrel asked:

Has someone already made a study of what level of cross-talk
could be tolerated between ALMA antennas?  This could be important
for ALMA because of the close packed configuration; also, at least
for the Vertex antenna, there isn't much additional attenuation in the
current design by backup structure or thermal insulation material for
anything that gets through the panel gaps. This makes it easier for the
feeds to see each other from one antenna to the next, through
the panel gaps.
   Does anyone have any comments on this, or has their already
been some study made?  Should we modify the thermal insulation
to block mm-waves, or consider using conductive tape behind
the gaps?  Is this an issue?

 If any study had been made for ALMA, I am unaware of one.