EVN Network Monitoring Experiment (NME) Pipeline Feedback
Last updated: Wed Mar 11 20:13:19 CET 2009
muehle@jive.nl
General Comments.
(
Brief data summary
and
scan listing
)
This is part 2 of the network monitoring experiment N08K4.
K band (22 GHz + 24 GHz) network monitoring experiment (NME) observed on 3 November 2008. The data rate was 256 Mbps (8 x 8 MHz subbands, dual polarization, two-bit sampling). The experiment consists of three parts: The first part is the regular NME at 22GHz with a setup similar to the user experiment EB037E. The last 1.5 hours of the schedule were dedicated to tests of the new VLBA 24GHz continuum setup (part 2) and an NH3 spectral line setup (part 3).
In part 1, the target source 'J2254+1341' was calibrated using the phase-reference source '3C454.3'. 'J1751+09', '3C345', '2037+511', and '0202+319' were also observed as calibrators. '3C454.3' served as fringe finder. The maser sources 'RCas' and 'UHer' were observed to provide additional diagnostics to the stations. Part 2 consists of long scans on the calibrator '3C454.3'. In part 3, the known NH_3 maser source in W51 'W51MASER' (Zhang & Ho 1991, ApJ 373, L13) was calibrated using the phase-reference source 'J1930+1532'. '3C454.3' was also observed as a calibrator.
9 stations participated in part 1. 6 stations participated in parts 2 and 3. Cm transmitted signal in only two subbands, due to the limitations of its microwave link. In part 1, this is IF3 and IF4, in part 2 IF1 and IF2, and in part 3, IF1 and ??? Mh did not participate in the ftp fringe-tests because of network problems. There were no fringes to Ys, probably due to a faulty IF LO. An exchange of the LO seems to have fixed the problem for the following user experiment EB037E. No fringes were found to Sh, either, the likely cause being a fault in the elevation axle. Nt had no RCP, thus fed the LCP signal to all BBCs. The erraneous data in the RCP channels have been flagged in the postcorrelation process. Jb showed strong RFI-like symptoms in the fringe test, which may be due to an RF-related fault in the high-patch channel. The fraction of high bits in the Jb data was close to zero, so that Jb had to be correlated as a 1-bit station and has a much reduced sensitivity.
The EVN reliability indicator (ERI) for this experiment was
ERI = 0.42 . ERI* = 0.42 .
(CM=1, EF=1, JB=0.5, ON=1, MC=1, NT=0.5, SH=0, MH=1, YS=0)
Plots of the autocorrelations
Comments.
Cm: limited bandpass, signal in IFs 1 and 2, check IF2/R+L; Jb: spiky bandpasses, possibly due to an RF-related fault in the high-patch channel; 4 pages
plots of the uncalibrated amplitude and phase
against time
Comments.
Cm: limited bandpass, signal in IFs 1 and 2, hectic phases; Jb: phases noisier than usual; otherwise, amplitudes and phases match expectations; 24 pages
Plots of the uncalibrated amplitude and phase
against frequency channel
Comments.
Cm: limited bandpass, signal in IFs 1 and 2; Jb: noisy phases (see comments above); 4 pages
The uncalibrated amplitude and phase of the crosshand
correlations against frequency channel
Comments.
nothing unexpected detected; 2 pages
TSYS against time
Comments.
Cm, Jb: T_sys set to 1; On: unusually high T_sys in IF4/R+L until ~17:22-24 UT = time when attenuators were put in? 5 pages
Telescope sensitivities
from the a priori TSYS and Gain
curves (the square of this number gives the antenna noise (SEFD) in Jy - the
smaller the better).
Comments.
very good match to "TSYS against time"; 5 pages
Fringe-fit phase solutions
(including Parallactic
Angle correction).
Comments.
refant = Ef; as expected, generally fast phases; 4 pages
Fringe-fit delay solutions
Comments.
refant = Ef; except for Cm, delays of the order of (a few) tens of nanoseconds; 4 pages
Fringe-fit rate solutions
Comments.
refant = Ef; rates of the order of mHz; 4 pages
Telescope bandpasses
Comments.
refant = Ef; nothing unexpected detected; 2 pages
Calibrated amplitude and phase against time
(a
priori amplitude calibration and fringe-fit solutions applied).
Comments.
refant = Ef; phases aligned, but still show significant deviations from zero, in particular Cm; Cm: IF2/R bad; Jb: phases in IF1-4/R noisier than usual; 16 pages
Calibrated amplitude and phase against frequency
channel
Comments.
phases deviate significantly from zero for Cm (and Jb); 4 pages
Naturally weighted dirty map (not useful for bright sources)
produced before self-cal of:
3C454.3: pdf (not available)
, or
FITS (not available)
.
Comments.
Uniformly weighted dirty map (not useful for bright sources)
produced before self-cal of:
3C454.3: pdf (not available)
, or
FITS (not available)
.
Comments.
Phase corrections applied to a priori calibrated and
fringe-fitted data by self-calibration.
3C454.3
.
Comments.
refant = Ef; only a few outliers; 4 pages
Amplitude corrections applied to a priori calibrated and
fringe-fitted data by self-calibration.
3C454.3:
pdf
, or
text file
, or
statistical summary
.
Comments.
significant gain corrections for Jb; 4 pages
Telescope sensitivities
(the total AMP gain applied
during both a priori and self calibration; the square of this number gives the
antenna noise (SEFD) in Jy).
Comments.
Jb: gain in IF1,3,4/R unusually high; 4 pages
Residual closure phase (visibility closure phase with model closure phase subtracted) for:
3C454.3
.
Comments.
some significant residuals; 2 pages
Calibrated visibilities and the source model of:
3C454.3
.
Comments.
Cm, Mc: some amplitude deviations in combination with poor phase alignment; Jb: phases noisier than usual in RCP (IF1-4); 15 pages
Calibrated visibilities against u,v distance for:
3C454.3:
pdf
, or
png
.
Comments.
u,v coverage for:
3C454.3:
pdf
, or
png
.
Comments.
Crude maps of sources:
3C454.3:
pdf
, or
FITS
.
Comments.