[evlatests] WIDAR data

[Walter Brisken]

Orion H2O maser EVLA data set orion23nov08

1. Ant 3, IFs 1,2,5,7 are bad.  bpass did a horrible job until these were
    explicitly flagged -- about 1 in 20 channels had a completely erratic
    value while the others were fine.

2. phase jump (expected?) at 05:18:33.  This is between offset setting #2
    and #3

3. Strong evidence of the sin(x)/x correlator spectral response from the
    maser in IF3 for all three frequency offsets.  No evidence in IF5 of
    such power.  This is completely countered by Hanning smoothing
    (smooth=1,0 in aips) as expected.

4. There is no evidence of a mirror image of in either the top end of IF3
    or the top end of IF4 within the noise limit.  The spectral dynamic
    range (peak channel flux density to RMS channel flux density) is at
    least 4000:1 (36 dB).

Additional details available upon request.

-Walter

On Mon, 24 Nov 2008, Michael Rupen wrote:

> 1. Walter, you're looking at Orion data.  The MS is available at
>   /home/phecda/MPR1/orion23nov08_000.54794.194721886575.ms   2.3 GB
>   The ready-to-examine UVFITS data set for AIPS  is
>    /home/phecda2/MPR2/orion23nov08_001.54794.25123326389.uvsrt  1.7 GB
>
>   The main maser line is in IF 4, leaking into IF 3.  The big question
>   is whether that leakage changes as I move to smaller antenna-based
>   frequency offsets.
>   * First 3 Orion scans use 10 kHz frequency offsets
>   * Next  2 Orion scans use  1 kHz frequency offsets
>   * Final 2 Orion scans use  0.1 kHz frequency offsets
>
>   Please check:
>   * "Leakage" from IF 4 (with line) into IF 3 (no line), as a function of
>     frequency offset