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<p>So, on a probably drier day, the effect is nearly invisible.
Support for the idea that water/dew on the window is a
contributing factor ...</p>
<p>Rick<br>
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<div class="moz-cite-prefix">On 8/27/21 9:42 AM, Drew Medlin wrote:<br>
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Here's an observation from a drier time of year. 2021-03-27,
afternoon observation, operator recorded Sky cover 40%. Cumuliform
clouds.
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<div class="">20A-092.sb39518402.eb39548999.59300.832225300925.ms-J0303+4716-bb12-PHASE-amp_vs_freq-LL_RR.png</div>
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<div class="">On Aug 27, 2021, at 9:18 AM, rperley <<a
href="mailto:rperley@nrao.edu" class=""
moz-do-not-send="true">rperley@nrao.edu</a>> wrote:</div>
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<div class="">Certainly is reasonable. In the case I
analyzed, the start of the run was around sunrise, the
end around noon. The period of the oscillations (and
the phase) did not appear to change, however. The
change in amplitude was quite obvious.<br class="">
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I don't know if there was rain on the day I looked at --
but perhaps dew on the window would do the trick ...<br
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Rick<br class="">
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On 2021-08-27 11:11, Ken Sowinski wrote:<br class="">
<blockquote type="cite" class="">On Fri, 27 Aug 2021,
Rick Perley via evlatests wrote:<br class="">
<blockquote type="cite" class="">Drew, et al.:<br
class="">
Perfect! Period shown in that C-band plot is about
100 MHz, which corresponds pretty closely to the
expected value corresponding to the length of the
horn. Good evidence for a mismatch between the
window and the OMT….<br class="">
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The change in the sinusoiid should correlate with
temperature.<br class="">
Might the reflections have been exacerbated by
moisture from<br class="">
all the recent rain?<br class="">
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