[evlatests] Baselines; Focus vs. elevation.

[Claire Chandler]

Hi Vivek,

I tried applying your antenna positions to my Q-band data and still see 
some pretty horrible phase wraps on antenna 24.  I can't say anything 
about the antennas that do not have Q-band receivers yet.  Is the position 
for antenna 24 particularly bad, or are these phase wraps caused by 
something else?

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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