\documentclass[preprint]{aastex} % AASTeXv5.0
\usepackage{carma_memo}
\usepackage{psfig}

\begin{document}

%%
%% CARMA Memo number. Check web http://www.mmarray.org/memos
%% for most recent memo number.
%%
\carmamemo{53}

%%
%% Uncomment these if this is also an ALMA or BIMA memorandum.
%%
%\almamemo{222} % ALMA Memo number.
%\bimamemo{101} % BIMA Memo number.


\title{Bandpass Calibration and Stability}
\author{Melvyn Wright$^1$}
\affil{Radio Astronomy Laboratory, U.C. Berkeley$^1$}

\begin{abstract}
In this memo we analyze the bandpass calibration from observations of
compact sources over periods of 1 hour, 1 day, and 2 months.
For these 500 MHz bandwidth observations, the bandpass is not
significantly flatter after applying the noise calibration.  The bandpass
is stable over a period of 1 day. No significant change was seen in
the astronomical bandpass between pointings in a mosaic over 0.7 hours
at the 0.4 to 1\% level for the 15 Carma antennas.  Similar residuals
were also obtained by applying the bandpass from the previous day.
However, over a period of 2 months, the bandpass does change at the 1 -
4 \% level.  If the bandpass is sufficiently stable, a recent observation
for a bandpass calibration can be re-used until it goes stale. This will
improve the scheduling and efficiency for many observations.

\end{abstract}

%%
%% Change Record/Revision History
%% This goes AFTER the abstract: the abstract is
%% printed on the front of the cover page and the
%% change record on the back of the cover page.
%% Use \addrevision to add additional revisions.
%% Columns are
%% | revision |date| author| sections/pages affected |
%% |          | remarks                              |

\ChangeRecordBegin
\addrevision{1.1}{2009-June-25}{MCHW}{1-14}{Draft memo}
\addrevision{1.2}{2009-July-14}{MCHW}{1-24}{edits, add plots}
\addrevision{1.3}{2009-July-24}{MCHW}{1-18}{edit text and figures}
\ChangeRecordEnd

\section{INTRODUCTION}

Accurate measurements of the instrumental bandpass are required for
many astronomical observations. For high signal to noise observations,
errors in the bandpass  can be larger than the thermal noise and
limit the accuracy of the data. At millimeter wavelengths, bandpass
errors affect spectral dynamic range, comparisons of spectral line
features in different molecular transitions, isotopic ratios, and MFS
observations. Measurements of the bandpass phase are critical when phase
referencing to a spectral line feature, such as in measuring the positions
of, or w.r.t. SiO masers. Bandpass calibration for CARMA is discussed in
BIMA memo 85 and CARMA memo 45. Bandpass calibration may require time
consuming and complex observational and data reduction procedures to
achieve the required accuracy (see CARMA memo 45), so it advantagous to
re-use the bandbass calibration if it is sufficiently stable.  In this
memo we analyze the bandpass obtained during hex7 mosaic observations
of 3C273 which were used to determine the aperture efficiency, pointing,
and primary beam of the CARMA antennas (CARMA memo 52).

\subsection{Bandpass, IF and RF frequency response}
The complex gain of the array is a function of time and
frequency. Most of the gain (amplitude and phase) is associated with
the signal path for each antenna, so that the gain can be
written as a product of the voltage gains for each antenna pair.  In
this case, the calibration can be antenna based resulting in a higher
signal to noise (SNR), and enhanced imaging performance resulting from
self calibration procedures. Any residual baseline based calibration,
such as closure errors in the correlator can be minimized and
eliminated if possible. E.g. by using orthogonal switching
patterns in the antennas and correlator.

Ideally, the time and frequency dependence can be separated as the product
of time dependent gains and frequency dependent bandpass measurements. In
practice the bandpass may be a slow function of time and require
periodic measurements, and the time dependent gains may be a function of
frequency. The poor SNR of an astronomical measurement of narrow bandwidth
IF characteristics in the bandpass requires an auxiliary measurement with
a noise source or using total power autocorrelations. The RF bandpass is
smoother and in a stable temperature controlled receiver environment,
and can be determined from periodic measurements of an astronomical
source. Traditionally this calibration has been the responsibility of
the observer, but in practice the calibration is done at a system level
to an accuracy of a few percent, and improving on this takes a large
amount of observing time. The typical user's bandpass calibration may
actually introduce systematic errors into the visibility data.
For example, the correlator may have phase offsets between the
wideband settings used for reference quasar measurements and the narrow
band setting used for spectral line source observations requiring a
wide-narrow-wide calibration sequence of the correlator.

A desirable goal is to provide a bandpass calibration which will suffice
for 80-90\% of the users, leaving the few observers who need a more
accurate bandpass to request and schedule time to do so. If the bandpass
is sufficiently stable, a recent observation for a bandpass calibration
can be re-used until it goes stale. This will improve the scheduling
and efficiency for many observations.  In this memo we analyze the
multichannel data from mosaic observation to determine the stability of
the instrumental bandpass.

\clearpage
\section{OBSERVATIONS AND DATA REDUCTION}

Observations were obtained using a standard hexagonal 7-pointing
mosaic of a strong compact source at the nominal pointing center and
half power points for the 10m antennas. The data are self-calibrated
to determine the antenna voltage gains. We used the MIRIAD
task {\bf mfcal} to determine the antenna-based gains versus time and bandpass.
The bandpass is determined w.r.t. the antenna gains. i.e. 

\[ G_{ij}~(t,f) = g_{i}~(t,f) \times g^*_{j}~(t,f)\]
\[ g_{i}~(t,f) = g_{i}~(t) \times b_{i}~(f)\]

$\bullet$ Solve for antenna gains, $g_{i}(t)$ as a function of time,
and solve for bandpass, $b_{i}~(f)$, as a function of frequency.

In addition to the astronomical observations, a noise source injected
at baseband can be used to calibrate the bandpass. This is especially
useful for narrow bandwidth observations where the signal-to-noise on
an astronomical source is poor. The noise source is phase switched to
appear as a lower sideband signal from the sky. For the noise source at
baseband, the bandpass in the upper sideband is the complex conjugate
of the lower sideband response, whereas for an astronomical source,
the bandpass has different RF bandpass responses in the upper and lower
sideband of LO1. The noise source can be used to correct astronomical
observations for the baseband response, but does not include the signal
path which preceeds the noise source injection. The correlator response
to the strong correlation from the noise source also differs from the
low correlation from astronomical sources.  In the following we compare
the bandpass obtained on the noise source with that obtained on an
astronomical source at different epochs.

\begin{verbatim}

Observation Log:

1) 09APR17:04:06:49.0  File: ct007.1C_1003C273.1.miriad
7-pointing mosaic at 95/100 GHz with  500 MHz BW.  Total observing time 0.73 hours

2) 09APR18:03:23:44.0   File: ct007.1C_1003C273.2.miriad
7-pointing mosaic at 95/100 GHz with  500 MHz BW.  Total observing time 0.89 hours

3) 09JUN24:23:22:35.5   File: ct007.1E_1003C273.1.mir
7-pointing mosaic at 95/100 GHz with  500 MHz BW.  Total observing time 0.70 hours

\end{verbatim}

\clearpage
\section{RESULTS}

\subsection{Noise source and Astronomical bandpass shapes}
Figures 1 \& 2 show the bandpass amplitude and phase measured on the
NOISE source on 09APR17.

Figures 3 \& 4 show the bandpass amplitude and phase measured on 3C273
on 09APR17.  The bandpass on the NOISE source is not the same shape as
the bandpass on an astronomical source.

Figures 5 \& 6 show the residual bandpass on 09APR17 for the3C273 central
pointing after applying bandpass correction from the NOISE source.  For
these 500 MHz bandwidth observations, the bandpass is not significantly
flatter after applying the noise calibration.  Similar results were
obtained for the 09APR18 and 09JUN24 observations.

\subsection{Bandpass Stability}

Figure 7 shows the residual bandpass amplitude for 3C273
on 09APR17 for an offset pointing after applying the bandpass correction
derived from the central pointing position in the hexagonal mosaic.
The astronomical bandpass changes slowly with time. No significant change
was seen in the astronomical bandpass between pointings in a mosaic
over 0.7 hours. The RMS residual across the bandpass is 0.004 to 0.011
(normalized to 1) for the 15 Carma antennas.
Similar residuals were also obtained by applying the bandpass from the
APR 17 observations of 3C273 to the APR 18 data. Figure 8 \& 9 show the
amplitude and phase residuals on the central pointing.

However, over a period of 2 months, the bandpass does change from APR
17 to JUN 24 (RMS residual 0.01 to 0.04) after applying bandpass. Figure
10 shows the amplitude residuals on the central pointing.

\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.NOISE.ct007.1C_1003C273.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude on NOISE source on 09APR17. Lower sideband at 93 GHz.  }
\end{figure} 

\clearpage 
\begin{figure} 
\psfig{figure=BandPass-Phase.NOISE.ct007.1C_1003C273.ps,angle=-90,width=6.0in} 
\caption{BandPass-Phase on NOISE source on 09APR17. Lower sideband at 93 GHz. 
}
\end{figure}

\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.3C273.ct007.1C_1003C273.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude on 3C273 central pointing on 09APR17. Lower sideband at 93 GHz. 
}
\end{figure}


\clearpage
\begin{figure}
\psfig{figure=BandPass-Phase.3C273.ct007.1C_1003C273.ps,angle=-90,width=6.0in}
\caption{BandPass-Phase on 3C273 central pointing on 09APR17. Lower sideband at 93 GHz. 
}
\end{figure}


\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.3C273.NOISE.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude residual on 09APR17 on 3C273 central pointing after 
applying bandpass correction from NOISE source.
}
\end{figure}


\clearpage
\begin{figure}
\psfig{figure=BandPass-Phase.3C273.NOISE.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Phase residual on 09APR17 on 3C273 central pointing after 
applying bandpass correction from NOISE source.
}
\end{figure}

\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.3C273.ct007.1C_1003C273.P1.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude residual on 09APR17 offset pointing after applying bandpass 
correction from 3C273 on central pointing position in hexagonal mosaic.
}
\end{figure}

%\clearpage
%\begin{figure}
%\psfig{figure=BandPass-Phase.3C273.ct007.1C_1003C273.P1.uvcal.ps,angle=-90,width=6.0in}
%\caption{BandPass-Phase residual on 09APR17 offset pointing after applying bandpass 
%correction from 3C273 on central pointing position in hexagonal mosaic.
%}
%\end{figure}

\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.ct007.1C_1003C273.2.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude residual on 09APR18 after applying bandpass correction from 
3C273 on previous day.
}
\end{figure}

\clearpage
\begin{figure}
\psfig{figure=BandPass-Phase.ct007.1C_1003C273.2.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Phase residual on 09APR18 after applying bandpass correction from 
3C273 on previous day.
}
\end{figure}

%\clearpage
%\begin{figure}
%\psfig{figure=BandPass-Amp.ct007.1E_1003C273.1.uvcal.ps,angle=-90,width=6.0in}
%\caption{BandPass-Amplitude residual on 09JUN24 after applying bandpass from 
%3C273 on 09JUN24
%}
%\end{figure}


\clearpage
\begin{figure}
\psfig{figure=BandPass-Amp.ct007.1E_1003C273.1.gpcopy.uvcal.ps,angle=-90,width=6.0in}
\caption{BandPass-Amplitude residual on 09JUN24 after applying bandpass from 
3C273 on 09APR17
}
\end{figure}

\clearpage
\section{CONCLUSION}
In this memo we analyze the bandpass calibration from observations of
compact sources in an interferometer mosaic pattern over a period of
2 months.  For these 500 MHz bandwidth observations, the bandpass is not
significantly flatter after applying the noise calibration.  The bandpass
is stable over a period of 1 day. No significant change was seen in
the astronomical bandpass between pointings in a mosaic over 0.7 hours
at the 0.4 to 1\% level for the 15 Carma antennas.  Similar residuals
were also obtained by applying the bandpass from the previous day.
However, over a period of 2 months, the bandpass does change at the 1 -
4 \% level.  If the bandpass is sufficiently stable, a recent observation
for a bandpass calibration can be re-used until it goes stale. This will
improve the scheduling and efficiency for many observations.

\clearpage
\section{ References }

Wei, L., Woody, D., Teuben, T., La Vigne, M., \& Vogel, S. 2008, CARMA memo 45,
{\it Bandpass Calibration for CARMA}

Wright, M., 2002, BIMA memo 85, {\it CARMA Calibration Requirements}

Wright, M., MacMahon, D., Corder, S., \& Sandell, G. 2009, CARMA memo 52
{\it Aperture Efficiency, Pointing and Primary Beam Calibration.}


\end{document}


\begin{verbatim}
 gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.3C273.uvcal nxy=3,5 yaxis=amp device=BandPass-Amp.3C273.ct007.1C_1003C273.uvcal.ps/ps
GpPlt: version 23-Jun-09
 Antenna 1   I-BandPass-Amp      ave, rms=  0.999991298  0.00415039062
 Antenna 2   I-BandPass-Amp      ave, rms=  0.999980271  0.00629106397
 Antenna 3   I-BandPass-Amp      ave, rms=  0.999976337  0.00687939581
 Antenna 4   I-BandPass-Amp      ave, rms=  0.999985278  0.00543726981
 Antenna 5   I-BandPass-Amp      ave, rms=  0.999972284  0.00745328981
 Antenna 6   I-BandPass-Amp      ave, rms=  0.999951482  0.00985675212
 Antenna 7   I-BandPass-Amp      ave, rms=  0.999985993  0.00530409208
 Antenna 8   I-BandPass-Amp      ave, rms=  0.999974489  0.00715960842
 Antenna 9   I-BandPass-Amp      ave, rms=  0.999969065  0.0078732986
 Antenna 10  I-BandPass-Amp      ave, rms=  0.999976933  0.0068184766
 Antenna 11  I-BandPass-Amp      ave, rms=  0.999937952  0.0111398771
 Antenna 12  I-BandPass-Amp      ave, rms=  0.999971747  0.00751302857
 Antenna 13  I-BandPass-Amp      ave, rms=  0.999992371  0.00389861315
 Antenna 14  I-BandPass-Amp      ave, rms=  0.999988914  0.00472145481
 Antenna 15  I-BandPass-Amp      ave, rms=  0.999985397  0.00539876567
/sun2/wright/carma/hex7> gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal device=/xs
GpPlt: version 23-Jun-09
 Antenna 1   I-BandPass-Amp      ave, rms=  0.999992371  0.00392147899
 Antenna 2   I-BandPass-Amp      ave, rms=  0.999991775  0.00403386494
 Antenna 3   I-BandPass-Amp      ave, rms=  0.999988496  0.0047591771
 Antenna 4   I-BandPass-Amp      ave, rms=  0.999989092  0.00467068516
 Antenna 5   I-BandPass-Amp      ave, rms=  0.99999243  0.00390625
 Antenna 6   I-BandPass-Amp      ave, rms=  0.999964237  0.00846432429
 Antenna 7   I-BandPass-Amp      ave, rms=  0.999993801  0.00349556189
 Antenna 8   I-BandPass-Amp      ave, rms=  0.999990106  0.0044417493
 Antenna 9   I-BandPass-Amp      ave, rms=  0.999967039  0.0081082629
 Antenna 10  I-BandPass-Amp      ave, rms=  0.999993205  0.00368644251
 Antenna 11  I-BandPass-Amp      ave, rms=  0.999994934  0.00320187421
 Antenna 12  I-BandPass-Amp      ave, rms=  0.999979734  0.00637576403
 Antenna 13  I-BandPass-Amp      ave, rms=  0.999989629  0.00456745271
 Antenna 14  I-BandPass-Amp      ave, rms=  0.999990404  0.00439453125
 Antenna 15  I-BandPass-Amp      ave, rms=  0.999986768  0.00512695312


gpplt options=bandpass nxy=3,5 vis=ct007.1E_1003C273.1.uvcal device=/xs
GpPlt: version 23-Jun-09
 Antenna 1   I-BandPass-Amp      ave, rms=  0.999998033  0.00201323512
 Antenna 2   I-BandPass-Amp      ave, rms=  0.999996603  0.00262947497
 Antenna 3   I-BandPass-Amp      ave, rms=  0.999999464  0.00109183008
 Antenna 4   I-BandPass-Amp      ave, rms=  0.999998569  0.00169145584
 Antenna 5   I-BandPass-Amp      ave, rms=  0.999997258  0.00232895324
 Antenna 6   I-BandPass-Amp      ave, rms=  0.999996603  0.00262947497
 Antenna 7   I-BandPass-Amp      ave, rms=  0.999999225  0.00122070312
 Antenna 8   I-BandPass-Amp      ave, rms=  0.999999762  0.000645935361
 Antenna 9   I-BandPass-Amp      ave, rms=  0.999999225  0.00124487781
 Antenna 10  I-BandPass-Amp      ave, rms=  0.999999583  0.000880261534
 Antenna 11  I-BandPass-Amp      ave, rms=  0.99999845  0.00185931963
 Antenna 12  I-BandPass-Amp      ave, rms=  0.999998033  0.00201323512
 Antenna 13  I-BandPass-Amp      ave, rms=  0.999997258  0.00236703129
 Antenna 14  I-BandPass-Amp      ave, rms=  0.999999642  0.000913490599
 Antenna 15  I-BandPass-Amp      ave, rms=  0.999998808  0.00148504949

/sun2/wright/carma/hex7> gpplt options=bandpass nxy=3,5 vis=ct007.1E_1003C273.1.gpcopy.uvcal device=/xs
GpPlt: version 23-Jun-09
 Antenna 1   I-BandPass-Amp      ave, rms=  0.999235034  0.0391036756
 Antenna 2   I-BandPass-Amp      ave, rms=  0.99955827  0.0297200475
 Antenna 3   I-BandPass-Amp      ave, rms=  0.996671796  0.0815188438
 Antenna 4   I-BandPass-Amp      ave, rms=  0.999910235  0.0134077445
 Antenna 5   I-BandPass-Amp      ave, rms=  0.999458849  0.0328974389
 Antenna 6   I-BandPass-Amp      ave, rms=  0.99951756  0.0310605988
 Antenna 7   I-BandPass-Amp      ave, rms=  0.999948144  0.0101751303
 Antenna 8   I-BandPass-Amp      ave, rms=  0.999860406  0.0167089254
 Antenna 9   I-BandPass-Amp      ave, rms=  0.999928355  0.0119703617
 Antenna 10  I-BandPass-Amp      ave, rms=  0.999611497  0.0278705526
 Antenna 11  I-BandPass-Amp      ave, rms=  0.999326169  0.0367056318
 Antenna 12  I-BandPass-Amp      ave, rms=  0.999789357  0.0205237921
 Antenna 13  I-BandPass-Amp      ave, rms=  0.999838173  0.0179903638
 Antenna 14  I-BandPass-Amp      ave, rms=  0.999895453  0.0144600514
 Antenna 15  I-BandPass-Amp      ave, rms=  0.999773085  0.0213102736
\end{verbatim}
Data reduction:

mfcal 'select=source(NOISE),-auto,window(1,2,3)' vis=ct007.1C_1003C273.1.miriad
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=phase
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=phase device=BandPass-Phase.NOISE.ct007.1C_1003C273.ps/ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=amp device=BandPass-Amp.NOISE.ct007.1C_1003C273.ps/ps
mfcal 'select=source(NOISE),-auto,window(1,2,3)' vis=ct007.1C_1003C273.1.NOISE.uvcal
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.NOISE.uvcal nxy=3,5 yaxis=amp device=BandPass-Amp.NOISE.uvcal.ps/ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.NOISE.uvcal nxy=3,5 yaxis=phase device=BandPass-Phase.NOISE.uvcal.ps/ps
gv BandPass-Phase.NOISE.uvcal.ps
gv BandPass-Amp.NOISE.uvcal.ps
mfcal 'select=-source(NOISE),-auto,window(1,2,3),dra(0),ddec(0)' vis=ct007.1C_1003C273.1.NOISE.uvcal
gpplt device=/xs options=bandpass dra(0),ddec(0)' vis=ct007.1C_1003C273.1.NOISE.uvcal nxy=3,5 yaxis=phase device=BandPass-Phase.3C273.NOISE.uvcal.ps/ps
gpplt device=/xs options=bandpass dra(0),ddec(0)' vis=ct007.1C_1003C273.1.NOISE.uvcal nxy=3,5 yaxis=amp device=BandPass-Amp.3C273.NOISE.uvcal.ps/ps
gv BandPass-Amp.3C273.NOISE.uvcal.ps
mfcal 'select=-source(NOISE),-auto,dra(0),ddec(0)' vis=ct007.1C_1003C273.1.miriad
mfcal 'select=-source(NOISE),-auto,dra(0),ddec(0),window(1,2,3)' vis=ct007.1C_1003C273.1.miriad
gpplt device=/xs options=bandpass yaxis=phase vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=amp device=BandPass-Phase.3C273.ct007.1C_1003C273.ps/ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=phase device=BandPass-Phase.3C273.ct007.1C_1003C273.ps/ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.miriad nxy=3,5 yaxis=amp device=BandPass-Amp.3C273.ct007.1C_1003C273.ps/ps
uvcal 'select=-auto,window(1,2,3)' vis=ct007.1C_1003C273.1.miriad out=ct007.1C_1003C273.1.NOISE.uvcal
mfcal 'select=-source(NOISE),-auto,dra(0),ddec(0),window(1,2,3)' vis=ct007.1C_1003C273.1.3C273.uvcal
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.3C273.uvcal nxy=3,5 yaxis=amp device=BandPass-Amp.3C273.ct007.1C_1003C273.uvcal.ps/ps
gv BandPass-Amp.3C273.ct007.1C_1003C273.uvcal.ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.3C273.uvcal nxy=3,5 yaxis=phase device=BandPass-Phase.3C273.ct007.1C_1003C273.uvcal.ps/ps
uvindex vis=ct007.1C_1003C273.1.miriad
mfcal 'select=-source(NOISE),-auto,dra(14.88),ddec(25.76),window(1,2,3)' vis=ct007.1C_1003C273.1.3C273.uvcal
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.3C273.uvcal nxy=3,5 yaxis=amp device=BandPass-Amp.3C273.ct007.1C_1003C273.P1.uvcal.ps/ps
gpplt device=/xs options=bandpass vis=ct007.1C_1003C273.1.3C273.uvcal nxy=3,5 yaxis=phase device=BandPass-Phase.3C273.ct007.1C_1003C273.P1.uvcal.ps/ps
gv BandPass-Amp.3C273.ct007.1C_1003C273.P1.uvcal.ps
gv BandPass-Phase.3C273.ct007.1C_1003C273.P1.uvcal.ps
uvcal 'select=-auto,window(1,2,3)' vis=ct007.1C_1003C273.1.miriad out=ct007.1C_1003C273.1.3C273.uvcal
gpcopy vis=ct007.1C_1003C273.1.miriad out=ct007.1C_1003C273.2.3C273.miriad
mfcal 'select=-source(NOISE),-auto,dra(0),ddec(0),window(1,2,3)' vis=ct007.1C_1003C273.2.miriad
gpcopy vis=ct007.1C_1003C273.1.miriad out=ct007.1C_1003C273.2.miriad
uvcal vis=ct007.1C_1003C273.1.miriad out=ct007.1C_1003C273.2.miriad out=ct007.1C_1003C273.2.uvcal
mfcal 'select=-source(NOISE),-auto,dra(0),ddec(0),window(1,2,3)' vis=ct007.1C_1003C273.2.uvcal
gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal
gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal device=/xs
gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal device=BandPass-Amp.ct007.1C_1003C273.2.uvcal.ps/ps
gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal yaxis=phase device=/xs
gpplt options=bandpass nxy=3,5 vis=ct007.1C_1003C273.2.uvcal yaxis=phase device=BandPass-Phase.ct007.1C_1003C273.2.uvcal.ps/ps
\begin{verbatim}
\end{verbatim}

