[evlatests] Strange Tcals and Switched Power behavior

[Ken Sowinski]

On Sun, 31 Oct 2010, Rick Perley wrote:

>    At L-band:  Most of the values are quite nonsensical.  Typical
> values are 20 to 50 K.  Some of them are over 200K.  One antenna (24, on
> all IFs) has *negative* values of Tcal.
>    A S-band,  the antennas with receivers have at least reasonable
> values in the table.  I note that antennas without receivers have
> reasonable values also -- one wonders how this can be ...
>    At C-band, three antennas, which produce decent fringes, have Tcal =
> 0.000  (Antenna 14 and 23 on all IFs, and antenna 16 on B and D IFs).
>    At X-band, all values look reasonable (but are they right?)

Rich has been working on this in mcaf and we should look at
it again when he has deplyed a new version.  Independently
Vivek is looking at how to verify that we have correct Tcals
in the parameters database.

>    I also note that antennas 10 and 24 are not detecting the
> synchronous power -- either the noise diodes are not switching, or the
> synchronous detection system is broken.  The reported values are all
> uniformly distributed about zero.  This is the case on all IFs, and at
> all bands.

Evidence is that the noise tubes are not turned off because
the are detected in the downconverters.  (I just checked this.)
That means that the antenna timing must be off by exactly
10 msec, or something is wrong with timing in all four station
boards connected to each of these antennas.  Rob, Bruce???