
In a standard calibration for heterodyne receivers, 
we observe 3 subscans, ``SAC'': 
on a Sky position,
an Ambient temperature load (a.k.a., ``hot'' load), 
and a ``Cold'' load.
Calibrations are always and automatically done in \total.

A calibration needs to be done for any heterodyne observation in order to
get data with a calibrated intensity scale.  It is normally done before
the target observations.  It must always be done after changing receiver
and/or backend setups.  It should also be done when changing sources
and often enough to follow any variation of the athmosphere, about
every 15 minutes.

\input{inc/pakoIncSaveCalibrate.tex}



