[mmaimcal] Q-band on ALMA

[Bryan Butler]

just to put some numbers on the relative sensitivity for extended
sources, you can write this like:

         / Bmax(VLA)  \ 2
r = p * | -----------  | 
         \ Bmax(ALMA) /

where Bmax(VLA) is the max baseline in the smallest configuration for
the VLA (D-config has Bmax(VLA) ~ 1 km), Bmax(ALMA) is the analagous
number for ALMA (compact array has Bmax(ALMA) ~ 200 m), and p is the
ratio of the point source sensitivities.  so, the brightness temp.
sensitivity for ALMA in the compact configuration will be about a
factor of 30 better than the VLA in the D-config.  this is a big
improvement.

i also agree with frazer's other points, though it's not clear to me
how large the fraction of time is when the array will be 'unusable' at
3mm...

	-bryan