[evlatests] Tests October 14

[Vivek Dhawan]

EA14 bandpasses look pretty good, though minor blemishes distinguish
them from the VLA.

IF A, RCP 50MHz   1 ns delay residual, amp slope no worse than VLA,
3.1MHz res.	  about a factor 2 across the band (except the last
		  channel).

IF A, LCP 50MHz	  ~0 ns residual delay; same amplitude slope as RCP.


IF A, RCP 25MHz	  ~ 1ns delay; buttonhook of ~80deg over ~2MHz at edge.
0.78 MHz res.	  (50degr over the first 1MHz)

IF A, LCP 25MHz	  ~0 ns delay; same buttonhook. amp slope only ~1.4
	          for both L and R.

I have some plots if mode details are needed.

Vivek.

Barry Clark wrote:
> For reasons unknown, antenna 16 was giving very weak fringes.  I didn't
> investigate why, but used antenna 14 only.  14 B is also very weak, and
> 14 C & D are weaker than they should be.
> 
> I tried out an amplitude corrected passband.  The effect on sensitivity
> is small, only three or four percent. (I didn't recheck delays, and my 
> coeffs change delay (by about 1 ns) relative to Mikes, so I'm not very
> certain of the magnitude of the improvement.)  I collected some data in 
> spectral line mode, at 50 and 25 MHz bandwidths, between 15:17 and 15:37 TAI,
> that it would be nice if somebody looked at it.
> 
> The passband seemed pretty reasonable, so I left it in.
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