[evlatests] Changing P-band Dipole orientations

[Rick Perley]

I noted yesterday some discrepant dipole orientations, and noted that I had the impression these were worse than at earlier times.

By happenstance, I'm calibrating some old (2019) P-band data for Tracy Clarke, which allows me to judge the correctness of that statement.

The statement is wrong.   Misorientations were worse in 2019 than now.

Tracy's data were taken twice – in March and in September of 2019.  The distribution of orientations were in fact worse than now, and also were very different.  Antennas misoriented now were better (or worse) in 2019.  Indeed, the correlation between the two 2019 observations is not very strong.

I believe these conclusions are not surprising, as the dipoles are known to be subject to rotation caused by the rotating subreflector.  Perhaps Rob Long can confirm this statment.

Rick
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