[evlatests] more on EVLAS and VLA subarrays

[Gustaaf van Moorsel]

Yesterday I reported the following:

> In preparation for the upcoming extended C-band projects, I did
> a test spectral line observation in two subarrays, one consisting
> of EVLA antennas in C-band, and one of VLA antennas in L-band.
> This had been successfully tested earlier with both subarrays in
> the same 4 IF mode.
> 
> This time the EVLA subarray observed in extended C-band with BW
> code 5, correlator mode 2AC (1.56 MHz bandwidth, 256 channels),
> and the VLA subarray in L-band with BW code 6, correlator mode
> 2BD (0.78 MHz bandwidth, 256 channels).  The results show good
> bandpasses on each antenna in either subarray.

The test as described above used BW code 5 for the first (EVLA)
subarray and BW code 6 for the second (VLA) subarray.  Both BW
codes result in the same number of channels (256), but a diff-
erent total bandwidth and channel width.  This choice was made
since one of the successful extended C-band proposers is int-
erested in using precisely this setup.

Ken suggested I also test a case where the number of channels
is different.  So I repeated the above test, with the differ-
ence that the VLA subarray now observed with BW code 4, or 128
channels.  The EVLA subarray remained unchanged, at BW code 5
and 256 channels.

The result of this second test is that whereas the second sub-
array (VLA) bandpasses look fine again, the subarray 1 (EVLA)
bandpasses are complete rubbish.

I will add this information to our EVLA web pages shortly.

Gustaaf