[evlatests] Antenna 14 FRM interference

[Frank Schinzel]

Hi everyone,

We did today a test today to verify the extend of the FRM interference 
from antenna 14 at 4 band. We observed Cas A at low elevation with the 
antennas facing West. We did one 5 min scan with the FRM off and another 
one with the FRM on. The interference clearly shows up. What surprised 
me the most is that cross-correlation products in IF6 show this as 
correlated interference present across the entire B array (see attached 
config.pdf).

For your enjoyment I have made comparison plots across the band for XY 
auto-correlations of antenna 14 (AC14_FRM_off.pdf, AC14_FRM_on.pdf, and 
AC14_FRM_on_zoom.pdf).

I also added an example of two cross-correlation plots with FRM on and 
off just showing IF6 XY (XC_FRM_off.ps and XC_FRM_on.ps). Those are for 
two baselines one between 14 and the neighboring antenna 23 and one 
where I didn't see strong interference in the cross-correlation between 
antennas 14 and 22.

It would be great if we could address this issue in the near future 
before we take some more 4-band data.

      Frank
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