[evlatests] Constant Squint

[Ken Sowinski]

On Mon, 15 May 2006, Rick Perley wrote:

>   At today's coordination meeting, Ken suggested that the values of the 
> EVLA antennas' squint (separation between RCP and LCP beams) as measured 
> by the pointing test last Saturday showed possibly variable values, from 
> which it could be inferred that the 'wiggle' pattern and/or solutions 
> obtained are faulty.
>   I have looked at the data quite carefully, and conclude that no such 
> variations occur.  The squint values are remarkably constant, for each 
> antenna and frequency

As usual we are both right.  Rick was looking at the Modcomp
pointing results and I was looking at the telcal pointing
results and there are interesting differences.

1.  telcal does not properly calculate the pointing offsets
and other parameters if one IF looks to be incorrect.  I
will look into this.

2.  Antenna 13 has a problem which causes it to give inaccurate
and therefore suppressed pointing results for some IF.  The other
EVLA antennas do not do this.  I do not propose we chase this
until more information is available to point the way.