polarization calibration

21nov01

    Polarization calibration  measures the phase and amplitude response of the system so that the stokes parameters of the source can be computed from the measured values. A linear matrix (the mueller matrix) is derived that maps the source parameters into the measured stokes parameters. Applying the inverse of this matrix to the measured stokes parameters gives the stokes parameters of the source.

The computation.
Parameter definitions.
The measurement results.
Source list.
800 Mhz rcvr results
lband wide results
lband narrow results.
sband narrow results.
sband wide results.
sband high results
cband results.
cband high results
xband results

History:

PolAPolB phase difference vs band frequency order.


Acquiring the calibration scan data:  (top)

Polarization calibration uses 2 cross scans rotated by 45 degrees centered on the expected source position. 
Each strip of a cross is 6 beam widths long and takes 60 seconds to traverse. A correlated cal is fired at the beginning of the pattern for calibration purposes (this is done 3 beam widths off source at the start of the first strip). A single pattern takes  5 to 6 minutes to complete. A polarized source is tracked from rise to get  good parallactic angle coverage. Sources close to 18 degrees dec (the latitude of the observatory)  should be avoided since the azimuth angle changes too rapidly to adequately sample the parallactic angle.

   The correlator is run in 3 level stokes mode. Each correlator board is fed both polarizations and computes the two autocorrelations and the two cross correlations. The online system transforms the two autocorrelations and computes the sum and difference to get I and Q. The cross correlation are combined into a complex correlation function and transformed. The real and imaginary parts then give U and V.  The spectra are returned normalized to the total power I.
 

Processing the data:

The processing stage uses the code of carl heiles to "correctly" amplitude and phase calibrate the data and then derive the mueller matrix elements. Let xx, yy be the normalized autocorrelations of the two polarizations and xy, yx be the normalized cross correlations. Px, Py will be the total power in pol A and B respectively. cosft() is the cosine transform and fft() is the complex fourier transform. A complex cross correlation (cacf) is also constructed. Assume there are N channels (a  zero lag and n-1 delays) Then cacf is:
cacf[0..2N-1]= yx[0:N-1] ,yx[N-1],  xy[N-1:1]
We duplicate the point yx[N-1] since we are 1 point short (there are two 0 delays : xy[0], yx[0] which are the same) and  2*(N-1) lags.

The online datatking computes:

I  =(Px*cosft(xx) + Py*cosft(yy))/(Px+Py)
Q=(Px*cosft(xx) - Py*cosft(yy))/(Px+Py)
U=  real(fft(cacf))*Px*Py/(Px+Py)
V=-img(fft(cacf))*Px*Py/(Px+Py)
This data is input for the calon/off and the 4 strips.  The processing is then:
  1. Recreate the individual polarization data and fixup U,V
    1.  
      XX=(I+Q)*.5*(Px+Py)
      YY=(I-Q)*.5*(Px+Py)
      U'=U*(Px+Py)
      V'=V*(Px+Py)
  2. Intensity calibrate the spectra using the cal. There are 4*60=240 spectra in the 4 strips.
    1. Each spectra has 128 channels. The <> operator below averages over channels [8:119]. Channels 0:7 and 120:127 where the filter changes rapidly are not used. The conversion from correlator counts to Kelvins is:
       
          XXcorToK= TcalXXK / (<XXcalOn>-<XXcalOff>)
          YYcorToK= TcalYYK / (<YYcalOn>-<YYcalOff>)

      Where TcalXXK, TcalYYK are the size of the XX, YY cals in Kelvins.
      The spectra are converted to Kelvins and then band pass corrected by dividing by the absolute value of the normalized cal off spectrum (the absolute value is needed since some of the points with small values close to the edge of the filter can be negative). The arrays used for calibration are:
       
          XXconv[0:127] = XXcorToK  /  (XXcalOff[0:127]/<XXcalOff>)
          YYconv[0:127]=YYcorToK  /  (YYcalOff[0:127]/<YYcalOff>)

      The intensity calibrated stokes parameters at each of 240 sampled points is then:
       
           Ical   =(XX * XXconv  + YY * YYconv)
           Qcal =(XX * XXconv   - YY * YYconv)
           Ucal =(U ' * sqrt(XXconv * YYconv))
           Vcal =(V '   * sqrt(XXconv * YYconv))
       
  3. Phase calibration.
  4. Fitting the beam and the sidelobes
  5. Computing the matrix elements.


   The  mueller matrix characterizes the system polarization response. Multiplying the source stokes vector by this matrix gives the measured stokes parameters. Use the inverse of the mueller matrix times the measured stokes parameters to get the source vector.

[I,Q,U,V]measured = MuellerMatrix               X [I,Q,U,V] source
[I,Q,U,V]source       = MuellerMatrixInverse X [I,Q,U,V] measured


Parameter definitions. (top)

    The parameters for the the polarization are described below (at least my attempt at describing them.. I don't claim that it is correct!!!). A more complete (and correct) description can be found in ATOMS 2000-5 (but good luck!!!).
  • alpha , x
  • is the coupling between the orthogonal input polarizations by a perfect horn. If Ex,Ey are the signals at the input to the horn, then
    Ea=  cos(alpha)Ex + e^(ix)*sin(alpha)*Ey
    Eb=-e^(ix)*sin(alpha)Ex + cos(alpha)*Ey
    are the voltages output by the horn. alpha is the mixing of the amplitudes and x is the phase delay introduced. Alpha projects the X,Y coordinate system of the input onto a coordinate system rotated by alpha. If you took the horn and physically rotated it by 15 degrees relative to the x,y coordinate system, then alpha= 15 degrees. Alpha assumes a perfect feed. The outputs remain orthogonal. For a perfect linear horn alpha=0,and x=0. For a perfect circular horn, equal parts of both linears are mixed with a 90deg phase delay so alpha=45deg, and x=90deg.
  • epsilon, phi
  • alpha,x measured the rotation,delay of a perfect feed. An imperfect feed will also have undesired cross coupling and phase delays. These could be caused by the linear probes in the waveguide not being orthogonal. The resulting polarizations will no longer be orthogonal. The input,output would look like:
    Eaa=  Ea + eps*e^(   i*phi)*Eb
    Ebb=  Eb + eps*e^(-i*phi)*Ea
    So a fraction eps of the other voltage gets added in with a phase delay of phi.
  • psi
  • A correlated cal is injected before the dewar into both polarizations. The phase difference through the receiver, iflo, cables, correlator.. is then measured by the phase difference of this correlated cal in the two polarizations. This is then removed. The resulting phase difference between the two polarizations of a astronomical source and that measured in the correlator is psi. If the cables from the single diode to the injection point have a different path length, then psi will be non-zero.
  • deltaG
  • The amplitude is calibrated using the cal values  for each polarization. deltaG is the relative error in these values Err(Ta-Tb)/(Ta+Tb). If you track a source with a linear feed then Q=(Ex^2-Ey^2) will not go to zero for an unpolarized source if deltaG is not zero.

    The measurement results:  (top)

        The results of the polarization calibration are listed below. It is broken down by receiver. For each receiver there are 1 or more frequencies where the mueller matrix was measured. There is a table that contains date, source, pol/mueller, freqDep, and gain/beam. The columns are:
  • col 1: date. The date when the data was taken
  • col 2: source. The source name.
  • col 3: pol/mueller. This contains a plot of the  fractional polarization Q, U, and V versus position angle. It also contains the values of the physical parameters and the computed mueller matrix. The plotted value depend on the type of feed. Linear feeds have: X-Y linear, XY linear, YX circular. Circular feeds give: X-Y=V, and  XY, YX are Q and U.
  • col 4: parameter dependence versus frequency
  • col 5: gain and beam charateristics.
  • col 6: measured source polarization.
  • Note: This data is remeasuring the mueller matrix each time. The current (when the data was taken) mueller matrix was not applied before analyzing the data (the mm_xxx routines were not used). The polarization properities of the source have not been corrected by the measured mueller matrix.

    Source list: (top)

    source receivers(# measurements) %pol
    B0017+154 800(1),lbn,(0),lbw(4),sbn(0)sbh(1),cb(1)  6.3 lb
    B0035+130 lbn(1)  
    B0106+013   9.7% nvss lb
    B0124+189 lbw(1) 5.0% nvss lb
    B0134+329 3C48 lbn(0),sbn(2),sbw(1)cb(7) .4% nvss lb
    B0340+048
    800(2),lbw(2),sbh(1)
    7.2% lb
    B0518+165 3C138 800(2),lbw(10),sbn(2),sbw(2),sbh(2),cb(5) 7.2% nvss lb
    B0534+342 lbw(2),sbw(1),sbh(1)  1.9% nvss lb
    J0603+219 lbn(1)  
    B0633+045 lbn(1)  
    J0725+144 lbw(1) 7% nvss
    B0824+294 lbw(2),lbn(3),sbn(0),cb(2),cbh(1) 3.7% nvss lb
    B0831+171 sbw(1)  .6% nvss lb
    B0838+133 lbw(4),lbn(6),sbn(1),sbh(1),cb(1) 1.9% nvss lb
    B0858+292
    sbh(1)

    J0935+086
    B0932+089
    lbn(1),sbh(1)  



    J0943+027 lbn(1)  
    J1017+275 lbn(1)  
    B1040+123 lbn(4),lbw(2),sbn(1),sbw(2),sbh(2),cb(3),cbh(1) 5.6% nvss lb
    B1140+223
    lbw(2),cb(1),cbh(1),
    1.0 lb
    B1218+339
    lbw(1),sbh(1)
    5.7%nvss
    B1328+254 cb(2),
    B1328+307 3C286 800(1),lbw(5),sbw(1),cb(2),cbh(2) 6.7% nvss lb
    B1317+179 lbn(1),lbw(1) 6.8% nvss lb
    B1442+101 lbw(1),lbn(0),sbn(1),sbw(1) 1.3% nvss lb
    B1535+139 lbw(1),cbh(1)pwd

    2.0% nvss lb
    B1602+014 cb(1)
    B1634+269 lbw(2) 3.9% nvss lb
    B1641+173 cb(1)
    B1756+134 cb(1)
    B1857+129 lbn(0),sbn(0),cb(1) .6% nvss lb
    B2041+170 lbw(1),lbn(0),sbn(1),cb(1) 6.3% nvss lb
    B2121+248 lbw(1)  
    B2209+080 lbw(3),lbn(1),sbn(1),sbh(4),cb(3) 4.4% nvss lb
    B2314+038 lbw(2),lbn(0),sbn(0),cb(1) 2.2% nvss lb
    B2230+114 lbn(1)  
    J2225+213 lbn(0),sbn(1)  
    B2247+140 lbn(0),sbn(1) .9% nvss lb
    B2249+185 sbn(1) 3.6% nvss lb


    800 Mhz rcvr results (top)

        The 800 Mhz rcvr is a native linear feed covering 700 to 800 Mhz. A high correlated cal is available. The current antenna (11mar11) is an 11 feed from byu (version 1). The frequencies for the measurements are:

    date
    source
    fracPol
    mueller
    vs
    freq
    measured
    % pol
    20jan11
    B0017+154
    fig
    fig .5,.6,.5,.6
    20jan11
    B0340+048
    fig fig 1.8,1.9,1.8,1.7
    09mar11
    B0340+048
    fig fig 1.8,1.6,1.3,1.4
    10mar11
    B0518+165
    fig fig 3.7,3.8,3.8,4.2
    11mar11
    B0518+165 fig fig 3.7,3.7,3.8,4.0
    15may12
    B1328+307
    fig
    fig
    4.0,5.4,2.8,6.5

    notes:



    lband wide results.  (top)

        Lband wide is a native linear feed. The receiver has a correlated cal to use for phase calibration. Data is taken in two frequency bands:
  • lbwlo 1175,1300,1375, and 1415 Mhz
  • lbwhi 1415, 1550, 1666, and 1610 Mhz
  • Warning: lbwlo data taken 18sep09 thru13jun15 (file .2) were taken with circular pol (hybrid in) rather than linear pol (hybrid out). They should not be used to compute the mueller matrix.
  • The dates were taken from the iflo header info in the files..


  •  
    col 1
    date
    col 2
    source
    col 3
    fracPol
    Mueller
    col4
    vs
    frq
    col 5
    gain,
    beam

    freqBand
    11aug01 B0518+165 fig fig fig lbwlo
    11aug01 B0838+133 fig fig fig lbwlo
    11aug01 B2314+038 fig fig fig lbwlo
    12aug01 B0518+165 fig fig fig lbwhi
    12aug01 B0838+133 fig fig fig lbwhi
    12aug01 B1634+269 fig fig fig lbwhi
    12aug01 B2041+170 fig fig fig lbwhi
    12aug01 B2314+038 fig fig fig lbwhi
    13aug01 B0124+189 fig fig fig lbwhi
    13aug01 B1634+269 fig fig fig lbwlo
    25sep01 B2209+080 fig fig fig lbwlo
    19nov01 B0838+133 fig fig fig lbwlo
    24dec01 B0824+294 fig fig fig lbwlo
    13apr02 B1535+139 fig fig fig lbwlo
    11oct02 B1328+307 fig fig fig lbwhi
    17feb03 NewLbw



    03mar03 B1040+123 fig fig fig lbwlo (1)
    03mar03 B1328+307 fig fig fig lbwlo (1)
    14may03 B2121+248 fig fig fig lbwhi
    10jul04 B0518+165 fig fig   lbwlo
    16sep04 B1442+101 fig fig   lbwlo
    20oct04 J0725+144 fig fig   lbwhi
    27apr05 B1040+123 fig fig   lbwhi
    14jul05 B1328+307 fig fig   lbwlo
    11dec05 B0534+342 fig fig   lbwlo
    23dec05 B0518+165 fig fig   lbwhi
    04jan06 B0518+165 fig fig   lbwlo
    26jan06 B0534+342 fig fig   lbwhi
    04aug06
    B0017+154
    fig fig
    lbwlo
    14oct06
    B0824+294
    fig fig
    lbwlo
    14oct06
    B1040+123
    fig fig
    lbwhi
    27oct06
    B0824+294
    fig fig
    lbwhi
    15nov06
    B0340+048
    fig fig
    lbwlo
    26nov06
    B1317+179
    fig fig
    lbwlo
    02dec06
    B1140+223
    fig fig
    lbwlo
    02dec06
    B1328+307
    fig fig
    lbwlo
    03dec06
    B1140+223
    fig fig
    lbwlo
    10dec06
    B1328+307
    fig fig
    lbwlo
    06jan07
    B0017+154
    fig fig
    lbwhi
    07jan07
    B0017+154
    fig fig
    lbwlo
    02feb07
    B0017+154
    fig fig
    lbwlo
    02feb07
    B0518+165
    fig fig
    lbwlo
    04feb07
    B0518+165
    fig fig
    lbwhi
    16sep08
    B0518+165
    fig fig
    lbwlo
    10feb09
    B0518+165 fig
    fig

    lbwhi
    26apr09
    B1218+339
    fig
    fig

    lbwhi
    10aug09
    B2209+080
    fig
    fig

    lbwhi
    02dec09
    B0518+165
    fig
    fig

    lbwlo
    28jun10
    B1535+139
    fig fig
    lbwhi
    30jun10
    B1535+139
    fig fig
    lbwlo
    23nov10
    B0518+165
    fig fig
    lbwhi
    16jan11
    B0340+048
    fig
    fig
    lbwlo
    25jan11
    B0824+294
    fig fig
    lbwlo
    08feb11
    B0518+165
    fig fig
    lbwlo
    09feb11
    B0838+133
    fig fig
    lbwlo
    27may12 B2209+080 fig fig
    lbwhi

    notes:

    procesing: x101/x102/allcal/lbw/, x101/x102/newcall/lbw


    lband narrow results. (top)

    lband narrow is a native circular feed. The polarization properties change rapidly as you move away from the center of the OMT. The receiver does not have a correlated cal for calibration purposes. The last column is the expected fractional polarizations. The values in () are the polarization angles on the sky. The analysis is deriving the mueller matrix. The measured polarization values have not been corrected by the computed mueller matrix.
        Updated through 01oct02.
     
    lband narrow at 1300,1375,1415,1500 Mhz. Native circular.
    date source fracPol
    Mueller
    vs
    frq
    gain,
    beam
    %pol 1400
    expected
    20apr01 B0838+133
    fig
    fig
    fig
    1.8 
    21apr01 B0838+133
    fig
    fig
    fig
    1.8 
    22apr01 B0035+130
    fig
    fig
    fig
    5.3 
    22apr01 B0838+133
    fig
    fig
    fig
    1.8
    22apr01 B1040+123
    fig
    fig
    fig
    6.1 (meas)
    22apr01 B2230+114
    fig
    fig
    fig
    4.5 
    23apr01 B1040+123
    fig
    fig
    fig
    5.6 (5.8 meas)
    09may01 J0935+086
    fig
    fig
    fig
    1.5 (nvss)
    10may01 J0943+027
    fig
    fig
    fig
    1.5(nvss)
    24may01 J1017+275
    fig
    fig
    fig
    4.9 (-77.5)
    05jun01 J0603+219
    fig
    fig
    fig
      .8(-59)
    05jun01 B0838+133
    fig
    fig
    fig
    1.8 
    05jun01 B1040+123
    fig
    fig
    fig
    5.6 
    24sep01 B2209+080
    fig
    fig
    fig
    5.7 (meas)
    03nov01 B0838+133
    processing: x101/x102/newcal/sbh/doall.profig
    fig
    fig
    1.8
    26dec01 B0824+294
    fig
    fig
    fig
    5.1 (meas)
    13feb02 B0824+294
    fig
    fig
    fig
     4.0 (meas) 
    13feb02 B1040+123
    fig
    fig
    fig
    7. 1 (meas)
    22feb02 B0824+294
    fig
    fig
    fig
    4.0 (meas)
    25feb02 B0633+045
    fig
    fig
    fig
    4.4 (meas)
    11jul02         (1*)
    13sep02 B1317+179
    fig
    fig
    fig
     6.9 (meas)
    20sep02 B0838+133
    fig
    fig
    fig
     2.4 (meas)
    1. 11jul02: cal values recomputed. new values backdated to 01sep02. Recomputed all the data.
    processing: x101/x102/allcal/lbn/


    sband narrow results at 2380 Mhz.  (top)

    Sband narrow at 2380 Mhz. Native circular.
    date
    source
    fracPol
    mueller
    vs 
    freq
    gain/
    beam
    measured
    % Pol
    05jan01 B1442+101
     fig
     fig
     fig
    1.0
    06jan01 B2247+140
    fig
     fig
     fig
    1.8
    08jan01 J2225+213
    fig
     fig
     fig
    9.2
    13jan01 B0134+329 (3C48)
    fig
     fig
     fig
    1.3
    13jun01 B0838+133
    fig
     fig
     fig
    3.2
    13jun01 B1040+123
    fig
     fig
     fig
    9.2
    25sep01 B0134+329(3C48)
    fig
    fig
    fig
    1.3
    25sep01 B0518+165(3C138)
    fig
    fig
    fig
    9.6
    27nov01 B2209+080
    fig
    fig
    fig
    6.4
    30nov01 B2249+185
    fig
    fig
    fig
    5.2
    01dec01 B2041+170
    fig
    fig
    fig
    10.7
    17feb06 B0518+165(3C138)
    fig
    fig
      9.5
    23nov06
    B1140+223
    fig
    fig

    02jan07
    B0453+227
    fig
    fig

    05jan07
    B0858+292
    fig
    fig

    08jan07
    B0932+089
    fig
    fig

    08jan07
    B0453+227
    fig
    fig

    13jan07
    B0017+154
    fig
    fig

    14jan07
    B1040+123
    fig
    fig

    27jan07
    B0534+342
    fig
    fig

    31jan07
    B0534+342
    fig
    fig

    01jan08
    B1040+123
    fig
    fig

    03jan08
    B1040+123
    fig
    fig

    04jan08
    B2209+080
    fig
    fig

    04jan08
    B1328+307
    fig
    fig

    04jan08
    B1140+223
    fig
    fig

    05jan08
    B0518+165
    fig
    fig

    07jan08
    B1328+307
    fig
    fig

    15jan08
    B1442+101
    fig
    fig

    19jan08
    B1140+223
    fig
    fig

    19jan08
    B0518+165
    fig
    fig

    20jan08
    B1140+223
    fig
    fig

    30jan08
    B0858+292
    fig
    fig

    01jan09
    B0534+342
    fig
    fig

    19jan09
    B1328+307
    fig
    fig

    20jan09
    B1328+307
    fig
    fig

    20jan09
    B1040+123
    fig
    fig

    01jan10
    B1040+123
    fig
    fig

    03jan10
    B0453+227
    fig
    fig

    04jan10
    B1535+139
    fig
    fig

    05jan10
    B0453+227
    fig
    fig

    10jan10
    B0109+144
    fig
    fig

    13jan10
    B1535+139
    fig
    fig

    15jan10
    B0109+144
    fig
    fig

    23jan10
    B0824+294
    fig
    fig

    07jan11
    B0453+227
    fig
    fig

    14jan11
    B0518+165
    fig
    fig

    16jan11
    B2209+080
    fig
    fig

    16jan11
    B0017+154
    fig
    fig

    07jan12
    B1328+307
    fig
    fig

    07jan12
    B1040+123
    fig
    fig

    29jan12
    B2209+080
    fig
    fig

  • 10apr06 installed new sbn cal values (hadn't been measured in years). backdated to be valid from 14oct03. The 17feb06 has the new cal value.
  • processing: x101/x102/newcal/sbn


    sband wide results at 2212, 2380, 2690, 2850 Mhz (top)

        Sband wide is a native linear receiver with a correlated cal.
     
     
    date source fracPol
    mueller
    vs 
    freq
    gain/
    beam
    measured
    %Pol
    19sep01 B1442+101 fig fig fig 1.1,1.4,1.8,1.8
    24sep01 B0518+165 3C138 fig fig fig 4.9,3.8,2.0,1.2
    23dec01 B0134+329 3C48 fig fig fig 1.2,2.0,1.8,1.6
    24dec01 B0518+165 3C138 fig fig fig 5.8,4.3,2.8,2.0
    24dec01 B1040+123 fig fig fig 4.4,3.7,2.9,1.9
    19feb02 B0534+342 fig fig fig  1.2,2.5,1.6,1.8
    20feb02 B0831+171 fig fig fig  1.2,2.1,1.3,1.2
    20feb02 B1040+123 fig fig fig 4.3,4.1,2.3,1.6
    20feb02 B1328+307 3C286 fig fig fig 9-10%
    21may03
    B1040+123
    fig
    fig

    04jun03
    B1140+223
    fig fig

    21aug04
    B0518+165
    fig fig

    22aug04
    B0340+048
    fig fig

    22aug04
    B0534+342
    fig fig

    31aug05
    B0518+165
    fig fig
    9.6,9.7,5.3,10.1
    26dec05
    B0518+165 fig fig

    11feb08
    B1328+307
    fig fig

    25sep08
    B0518+165 fig fig

    20sep09
    B0518+165
    fig fig

    12sep10
    B0453+227
    fig fig


    Notes:


    processing: x101/x102/newcal/sbw

    sband high results.

        sband high is a native linear feed covering 3 to 4 ghz.

    date source fracPol
    mueller
    vs 
    freq
    measured
    %Pol
    28jun04
    B0017+154
    fig
    fig
    26aug04
    B0340+048
    fig fig
    21may04
    B1040+123
    fig fig
    24jun04
    B2209+080
    fig fig
    17may05
    B1040+123
    fig fig
    22may05
    B2209+080
    fig fig
    20jul05
    B2209+080
    fig fig
    23jan06
    B0518+165
    fig fig
    14may06
    B0932+089
    fig fig
    13jan10
    B0518+165
    fig fig
    02feb10
    B0534+342
    fig fig
    15may11
    B0858+292
    fig fig
    17may11
    B2209+080
    fig fig
    18may11
    B0838+133
    fig fig
    19may11
    B1218+339
    fig fig
    13feb15
    B1328+307
    fig fig
    03mar15
    B1317+179
    fig fig


    processing: x101/x102/newcal/sbh/doall.pro


    cband results.  (top)

        Cband is a native linear receiver with a correlated cal. The calibration routines are run in a high or low mode. The frequencies for the two modes are:

  • LL: 4100,4400,4700,5000
  • C: center  4500, 4860, 5000, and 5400 Mhz
  • H:high  5000,5400,5690, and 5900 Mhz

  • The H, or L in the dat column signifies a high  or low frequency run.
    cband results
    date source
    fracPol
    mueller
    vs 
    freq
    gain/
    beam
    source
    Pol %file='/share/olcor/corfile.14oct12.x102.1'
    n=mmproc(file,scndata,mm,hb_arr,beamin_arr,beamout_arr,/phaseplot,/plot1d,/plot2d)
    save,mm,file='mm.sav'

    31jan01C B2209+080
    fig
    fig
    fig
    7.0/10.1/7.1/8.9
    01feb01C B0017+154
    fig
    fig
    fig
    15.7/15.6/15.9/16.2
    02feb01C B0134+329(3C48)
    fig
    fig
    fig
    5.1/5.6/5.7/6.1
    28jun01C B0134+329(3C48)
    fig
    fig
    fig
    3.1/3.9/3.6/4.2
    03aug01C B1857+129
    fig
    fig
    fig
     4.9/5.1/5.2/5.7
    03aug01C B2041+170
    fig
    fig
    fig
     11.7/11.3/11.6/11.5
    03aug01C B2314+038
    fig
    fig
    fig
     2.1/2.2/2.2/2.7
    05aug01C B1641+173
    fig
    fig
    fig
    .9/.5/.7/.8
    04nov01C B0824+294
    fig
    fig
    fig
     5.8/5.7/5.6/5.6
    17nov01C B0838+133 
    fig
    fig
    fig
    2.3/2.0/2.0/1.6
    22dec01C B0134+329(3C48)
    fig
    fig
    fig
    4.5/4.9/4.9/5.3
    23dec01C B0518+165(3C138)
    fig
    fig
    fig
    11.7/11.3/11.4/11.1
    26dec01C B1040+123
    fig
    fig
    fig
    9.3/9.0/9.1/9.0
    31jan02C B0134+329(3C48)
    fig
    fig
    fig
    3.9/4.4/4.4/4.9
    10apr02H B1328+254
    fig
    fig
    fig
    5.1/5.0/4.9/4.4
    10apr02H B1602+014
    fig
    fig
    fig
    1.3/1.8/2.5/3.2
    10apr02H B1756+134
    fig
    fig
    fig
    3.2/3.5/3.9/3.9
    06feb08C B0518+165
    fig
    fig

    10.9/11.2/11.0/10.5
    20may08L
    B1328+307
    fig
    fig
    10.5/10.5/10.3/10.4
    29jul08C
    B0134+329
    fig fig
    4.6/5.0/5.2/5.7
    07nov08L
    B1040+123
    fig fig
    10.9/11.1/11.2/11.3
    08nov08H
    B1040+123
    fig fig
    11.5/11.4/11.3/11.2
    20feb09H
    B0518+165
    fig fig
    10.8/10.4/10.1/9.4
    02apr09C
    B1328+307
    fig fig
    10.5/10.5/10.5/10.6
    26apr09C
    B1140+223
    fig fig
    5.7/5.7/5.7/6.0
    24oct09C
    B0824+294
    fig fig
    5.3/5.3/5.3/5.2
    01nov09C
    B2209+080
    fig fig
    6.1/6.0/5.9/5.7
    01nov09C
    B0134+329
    fig fig
    4.6/4.7/5.0/5.4
    01dec09C
    B0518+165
    fig fig
    10.4/10.5/10.5/10.1
    16nov10C
    B0518+165
    fig
    fig
    10.2/10.8/10.7/10.2
    17dec10C
    B0518+165
    fig fig
    10.7/10.7/10.0/9.5
    31may12H
    B2209+08
    fig fig
    6.0/6.1/6.0/5.9



    processing:x101/x102/newcal/cband/doall.pro


    cband high results:  (top)

        Cband high covers 6 to 8 ghz. Its is a native linear receiver. The dewar was designed for dual beam for continuum measurements, but the second horn was never installed. The receiver has a number of resonances across the band (more info). This makes it pretty hard to get good stokes data. In particular you need to look  at deltag  in the plots. This is the computed error in the cal difference (polA-polB). It gets up to 20% for some frequency regions.

    cband high results
    date source fracPol
    Mueller
    vs
    frq
    source
    Pol%
    freqUsed
    Mhz
    10mar09
    B1040+123
    fig
    fig
    11.4,11.0,11.1,10.7
    6600,6900,7200,7400
    11mar09
    B0824+294
    fig
    fig 6.3,4.7,5.8,6.8
    6600,6900,7200,7400
    01may12
    B1328+307
    fig fig 10.4,10.7,11.0,11.1
    6035,6105,6300,6678
    01may12 B1535+139
    fig fig 3.9,3.8,3.8,3.8
    6035,6105,6300,6678
    08may12
    B1328+307
    fig fig 11.4,9.9,x.x,12.3
    6650,6900,7200,7400

    processing:x101/x102/newcal/cbh


    xband results (top)

        xband covers 7.8 to 10ghz. It is a native circular receiver.

    date
    source
    fracPol
    Mueller
    vs
    frq
    source
    Pol%
    freqUsed
    Mhz
    19jul02 B1040+123 fig fig

    01jun03 B1040+123 fig fig

    08sep03 B2209+080 fig fig

    17sep03 B0534+342 fig fig

    18sep03 B0518+165 fig fig

    11oct03 B2209+080 fig fig

    23nov03 B0518+165 fig fig

    12jun04 B1040+123 fig fig

    13jun04 B1040+123 fig fig

    13jun04 B1328+307 fig fig

    14mar04 B1140+223 fig fig

    14mar04 B1328+307 fig fig

    05dec04 B0518+165 fig fig

    17jan05 B0518+165 fig fig

    06mar05 B0518+165 fig fig

    19jul05 B2209+080 fig fig

    24jan06 B0518+165 fig fig

    24feb06 B0518+165 fig fig

    18feb07 B0518+165 fig fig

    07feb08 B0518+165 fig fig

    16sep08 B0518+165 fig fig

    20dec08 B1328+307 fig fig

    01mar09 B0518+165 fig fig

    19dec09 B1328+307 fig fig

    21dec09 B0518+165 fig fig

    04mar12 B0518+165 fig fig

    12may12 B1328+307 fig fig


    processing:x101/x102/newcal/xb


    Miscellaneous


    14dec09: Flipping the band changes the sign of the  polA,polB phase difference (stokesV): (top)

        Data taken in dec09 with cband and the mock spectrometer showed that the sign of stokes V   changed depending on the sideband of the output data.

    Setup:

    Processing:

    The plots show the cal deflection after calibration (.ps) (.pdf):

    This plot shows that phase is flipped when the band is flipped (.ps) (.pdf):

    Summary:

    processing: x101/091204/stokes_cbtest.pro, chkphasemixing.pro

    History:


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