Notes: This table contains the characterics of devices used for the calibration. NUM_RECEPTORS is
known through the FEED_ID. The load observed at a given time is specified in the STATE table via
the item CALLOAD_NUM when REF is TRUE. Note that a single row MAIN table is associated to a
given state as indexed from STATE_ID , this state being identical for all the involved antennas i.e. the
members of the ANTENNA_ARRAY collection. This state has parameters which may be different from
one antenna, feed, spectral window combination to an other as described here concerning the calibration
devices.
Note that Nr, the number of receivers, is specified in the FEED table.
N.B.: Additional calibration device properties will have to be defined if necessary.
Spectral window identifier. A value of -1 indicates the row is
valid for all spectral windows. If a specific spectral window has its own feed characteristics
these have to be defined separately using a value > 0, to override the global specifications
for that specific window.
TIME
Mid-point of time interval for which the parameters in the row are valid. The same
reference used for the TIME column in the MAIN must be used.
INTERVAL
Time interval. It should be the same as in the FEED table.
NUM_CALLOAD
Number of calibration noise or load Nload available for this feed.
NCAL
Noise calibration temperatures (0 if not added) Either NCAL or TLOAD must be
provided but not both simultaneously.
TLOAD
Physical temperatures of the load for each calibration device. Either NCAL or
TLOAD must be provided but not both simultaneously.
CALEFF
Calibration device efficiency/coupling efficiencies. These efficiencies may not be
strictly identical for the different receivers.