The variation in signal path length from antenna to correlator (caused
by temperature changes etc) is monitored by a program called rt
(run
on a computer in the screened room). A program on XBONES
called LOMON loads these values into a XBONES global common
area and CAOBS uses the values to correct phase errors caused by these
changes. LOPLOT displays these variations and ASSISTANCE
monitors the values, and reports an error if the values do not change
with time. However, the variations are normally quite small, so you
can get spurious error messages.
You can also get some real problems!