[evlatests] Baselines; Focus vs. elevation.

[Claire Chandler]

Hi Vivek,

It cannot be the case that the antenna positions changed when the focus 
vs. elevation corrections were turned on, so I don't understand why there 
should be two separate sets of solutions for before and after March 12. 
Rather, the positions you derive prior to March 12 have incorporated the 
phase vs elevation into the antenna positions and are incorrect.  It seems 
to me that the corrections you list as being valid post-March 12 are the 
ones to use for all D configuration data.

Claire

On Wed, 14 Mar 2007, Vivek Dhawan wrote:

>
> I now have solutions for EVLA antenna positions.
>
> They work, i.e., when applied, the phase residuals drop from
> 100's of degrees to 10 or 20 deg, and are consistent from day
> to day. The offsets are a bit higher than is usual for VLA
> antennas, which makes me suspect that the phase variation from
> the electronics is inflating the fitted offsets. However, it
> is certainly better to apply them than not.
>
> Corrections applicable to data from 2007 March 12 onward are
> in the first table, in CLCOR-ready format, offsets in m.
> This table is for focus vs. elevation ON (corrected online).
>
> Though not the dominant contribution, the foc/el correction
> changes the fitted offsets:
>
> dX(off) = dX(on) + 7.5 mm (error about +_ 1mm)
> dY(off) = dY(on)
> dZ(off) = dZ(on) + 4.5 mm
>
> To correct EVLA data taken with foc/el OFF - i.e. after the
> last move and before March 12, use the second table.
>
>
> -------- FOCUS vs. ELevation ON ---------------------
> valid 2007 March 12 to 15.
>
> These offsets will go into the database later (tomorrow?)
> after which they should NOT be applied in post-processing.
>
> task clcor; opcod 'antp'; gainver 0; gainu 0;
> antenn 13, 0
> clcorp  0.020,  -0.005,   0.002; go clcor; wait clcor;
> antenn 14, 0
> clcorp  0.020,   0.012,  -0.006; go clcor; wait clcor;
> antenn 16, 0
> clcorp  0.023,   0.019,  -0.015; go clcor; wait clcor;
> antenn 17, 0
> clcorp -0.009,  -0.015,  -0.014; go clcor; wait clcor;
> antenn 18, 0
> clcorp -0.002,   0.010,  -0.005; go clcor; wait clcor;
> antenn 23, 0
> clcorp  0.004,   0.010,  -0.010; go clcor; wait clcor;
> antenn 24, 0
> clcorp -0.007,   0.003,  -0.002; go clcor; wait clcor;
> antenn 26, 0
> clcorp -0.019,   0.012,   0.004; go clcor; wait clcor;
>
> ------------------------------------------------------
>
> -------- FOCUS vs. ELevation OFF - -------------------
>
> Valid XX to 2007 March 12, where XX = date of last move
>
> ea13 Feb13     ea14 Jan17     ea16 Jan17     ea17 Feb21
>
> ea18 Feb21     ea23 Jan29     ea24 Jan16     ea26 Oct18
>
> task clcor; opcod 'antp'; gainver 0; gainu 0;
> antenn 13, 0
> clcorp  0.027,  -0.005,   0.006; go clcor; wait clcor;
> antenn 14, 0
> clcorp  0.027,   0.012,  -0.001; go clcor; wait clcor;
> antenn 16, 0
> clcorp  0.030,   0.019,  -0.011; go clcor; wait clcor;
> antenn 17, 0
> clcorp -0.002,  -0.015,  -0.010; go clcor; wait clcor;
> antenn 18, 0
> clcorp  0.005,   0.010,  -0.000; go clcor; wait clcor;
> antenn 23, 0
> clcorp  0.011,   0.010,  -0.005; go clcor; wait clcor;
> antenn 24, 0
> clcorp  0.001,   0.003,   0.004; go clcor; wait clcor;
> antenn 26, 0
> clcorp -0.010,   0.012,   0.009; go clcor; wait clcor;
>
> ------------------------------------------------------
>
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