[evlatests] Consequence of IAT clock error

[Claire Chandler]

Are there tests that should be done during start up that could check for 
this in the future?

Claire

On Tue, 8 Jan 2008, Rick Perley wrote:

>    The clock error which was found and corrected yesterday appears to
> have resulted in the following:
>
>    a) A loss of ~ 25% in sensitivity on EVLA to VLA baselines
>    b) Closure errors of up to 100% on EVLA to EVLA baselines.
>
>    Hence, data taken from the time the clock error began (probably
> Thursday during maintenance time -- but this has yet to be established)
> until its correction (during software time yesterday) are severely
> compromised.  Users should flag their EVLA to EVLA baselines.  EVLA to
> VLA baselines do not show any closure problems, but are reduced in
> sensitivity.  VLA to VLA baselines are unaffected.
>
>    I believe that the new 'L350 1PPS' device, soon to be implemented,
> should eliminate this kind of mis-timing.  Testers should note that by
> far the easiest way to detect this problem is to set the closure report
> level (within CALIB) at 50% or so.  (I had discontinued looking at
> closure myself because of the large number of moderate level (10 -- 20%)
> errors from the bandpass mismatch problem was cluttering up the screens).
> _______________________________________________
> evlatests mailing list
> evlatests at listmgr.cv.nrao.edu
> http://listmgr.cv.nrao.edu/mailman/listinfo/evlatests
>