[evlatests] Phased array, modcomp-free : does not work.

[Ken Sowinski]

On Thu, 14 Jun 2007, Vivek Dhawan wrote:

> The test ran 2007-06-14 from 23:54 to 01:10.
>
> X band, 2min scans alternating on two standard calibrators
>         0921+622 (autophasing VA mode) and  0903+679 (VX mode)
>         integration time 1.6s
>
> Results are truly strange. Apart from "its broken" I offer these
> details:
>
> 1. There are fringes on every baseline for the last 90sec of Jun 14th.
>    Every 10sec the phase jumps to a new value and is flat for 10 sec.
>    These fringes are on the VA calibrator, and are about the strength
>    expected.
>
> 2. For the rest of the run, fringes appear on only baseline 6-13
>    and no other baseline.

It is clear from the correlator log that the system controller
go timestamps at IAT midnight that it was not prepared to deal
with.  From that time on it appears the correlator did not work
properly and only returned to normal when the system controller
was rebooted.

I would predict that Gustaaf's tests which followed this also
failed.  Certainly the observations following Gustaaf's test
in the way described by Vivek.

More investigation is needed.