Things to watch:
Shadowing of close antennas (e.g. 30m baseline: elevation should be > 35 - 45 degrees)
set attenuators manually (disable auto)
stay away from clouds and the Sun
No frequency tuning needed !! (great)
Delays are stable in 3mm band (no cacal)
Planets are good calibrators (sched files)
SiO masers are booming in !