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Basic Information on mfcal
Purpose: Multifrequency antenna and passband calibration.
MfCal is a Miriad task which determines calibration corrections
(antenna gains, delay terms and passband responses) from a
multi-frequency observation. The delays and passband are
determined from an average of all the selected data. The gains
are worked out periodically depending upon the user set interval.
Input visibility data file. No default. This can (indeed should)
contain multiple channels and spectral windows. The frequency
set-up can vary with time.
Standard line parameter, with standard defaults.
Stokes parameters to process. The default is to process the parallel
The number of channels, at the edges of each spectral window, that
are to be dropped. Either one or two numbers can be given, being the
number of channels at the start and end of each spectral window to be
dropped. If only one number is given, then this number of channels
is dropped from both the start and end of each window. The default
value is 0.
Standard uv selection. The default is to select all data.
Three to five numbers, giving the source flux density, a reference
frequency (in GHz) and the source spectral index parameters.
The flux and spectral index parameters are at the reference frequency.
If no values are given, then MFCAL checks whether the source is one
of a set of known sources, and uses the appropriate flux variation
with frequency. Otherwise the default flux is determined so that
the rms gain amplitude is 1, and the default spectral index is 0.
The default reference frequency is the mean of the frequencies in
the input data. Also see the `oldflux' option.
The reference antenna. Default is 3. The reference antenna needs
to be present throughout the observation. Any solution intervals
where the reference antenna is missing are discarded.
The minimum number of antennae that must be present before a
solution is attempted. Default is 2.
This gives one, two or three numbers, all in units of minutes, being
used to determine the lengths of the antenna gain and passband
calibration solution interval.
The first gives the maximum length of a gain solution interval.
The default is 5 minutes.
The second gives the maximum gap size in a gain solution interval.
A new solution interval is started when either the max length is
exceeded, or a gap larger than the max gap size is encountered.
The default default max gap size is the same as the max length.
The third number specifies the passband solution interval.
The default is a single passband solution for the entire observation.
Each passband solution interval will consist of one or more
full gain solution intervals.
Extra processing options. Several values can be given, separated by
commas. Minimum match is used. Possible values are:
delay Attempt to solve for the delay parameters. This can
be a large sink of CPU time. This option rarely works and
should be used with caution.
nopassol Do not solve for bandpass shape. In this case if a bandpass
table is present in the visibility data-set, then it will
be applied to the data.
interpolate Interpolate (and extrapolate) via a spline fit (to
the real and imaginary parts) bandpass values for
channels with no solution. This is commonly used because
a set of channels are flagged, possibly because of RFI or
spectral features in the bandpass calibrator. If
less than 50% of the channels are good, the
interpolation (extrapolation) is not done and those
channels will not have a bandpass solution
oldflux This causes MFCAL to use the pre-August 1994 ATCA flux
density scale below 11 GHz and and the pre-May 2016 mm
fluxscale above 11 GHz.
See the help on oldflux for more information.
Solution convergence tolerance. Default is 0.001.
Revision: 1.21, 2021/06/02 04:45:09 UTC
Generated by email@example.com on 02 Jun 2021