[evlatests] Antenna 5 Bandpass

[Rick Perley]

    A concern was expressed this morning  with the bandpass of antenna 5 
at L-band.  I checked the Hercules A 'demo project' data, taken August 
28.  There is a curious effect, not seen earlier (by me) in the RCP 
polarization of this antenna. 

    ea05, in RCP, shows a fine-scale frequency ripple -- only 5 MHz!   
This is seen in both amplitude and phase, consistent with a reflection 
of length ~30 meters!  This fine ripple is seen only in this antenna, in 
that one polarization.  The amplitude of the ripple is quite small: 
pk:pk less than 5% (and about 2 degrees in phase).   This length is 
certainly longer than anything in the antenna optics or normal signal 
path. 

    I will check the earlier data (taken in March) for the presence of 
this ripple.