[evlatests] More on drops

[Rick Perley]

    I reviewed the 'drop data' from yesterday, and gleaned a few more 
characteristics.  Perhaps these will be useful for those who understand 
the system ...

    A)  All drops occur on, and only on, a 10-second period.   But the 
'epoch' of the drop is never on a ten-second tick (i.e., at 10.0, 20.0, 
30.0, etc.)  We found three distinct, and unique drop epochs (meaning, 
only one is operating at any one time).  I reviewed the data more 
carefully to get a more precise time.  These are
          'On the 1's:  The drops occur 1.2 seconds (three data dumps) 
after the 10-second ticks. 
          ' On the 4s':  These occur at 4.2 or 4.6 seconds following the 
10-second tick. 
          ' On the 5s':  These are at 4.6 seconds following the 
10-second tick.  They may in fact be the same
as 'on the 4s'. 

    B) I note that the drops don't 'close'.  This is best illustrated by 
an example:  The last family of drops we noted yesterday occurred 'on 
the 4s', with antennas 13 and 24 doing it.  (Antenna 24 only has an AC 
side, and antenna 18 does not drop on that side).  Antenna 1 x 24 showed 
an amplitude drop to 0.23 of the non-drop level. 
Antenna 1 x 13 showed a drop to 0.50 of the non-drop level.  But antenna 
13 x 24 dropped only to 0.78 of the non-drop, not to the 0.12 you'd 
expect if these drops were simply multiplicative. 
    I also checked this characteristic for the 'on the 1s' family of 
drops.  For baseline 1-13, the drop was always to a level 0.76 of the 
proper amplitude.  For baseline 1-18, we got *either* 0.65 or 0.24 of 
the proper height.  For 13 x 18, the drop was to 0.88 (not 0.76*0.65 = 
0.50), or 0.13 (not 0.76*0.24 = 0.18) of the undropped amplitude.  So 
these don't 'close' either. 

    C)  I remind everybody that antennas 14 and 16 show no drops 
whatsoever.  Also, antenna 18 on the
AC side shows no drops at all. 

    D) For all drops, there is no visible phase effect.