[evlatests] Antenna 18, C-band phase jumps

[Emmanuel Momjian]

Antenna 18's C-band observations are showing phase jumps up and down 
between two states that are separated by about 60 degrees.

Most of the time, these two states seem to be associated with the short 
shallow drops seen in the amplitude solutions, i.e., when a short 
shallow drop occurs in amplitude, the phases jump up or down by ~60 
degrees, and return back to their original value following another short 
shallow drop in amplitude, and so on. However, in some instances, the 
phase jump occurs with no corresponding short shallow drop in amplitude.

Based on the test data I have from various days, these phase jumps are 
seen in the C-band observations of Nov. 13, 16, 17, 19, and 26. However, 
they are not seen in the C-band observations of Nov. 5.