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<p>Hi Rick, Rob-</p>
<p><br>
</p>
<p>Climbed ea11 today with some visitors, and mused about the P-band
dipole orientation. FWIW...<br>
</p>
<p><br>
</p>
<p>Get out your protractors:</p>
<p><br>
</p>
<p><img src="cid:part1.OL2ERado.po4sOH1n@nrao.edu" alt=""></p>
<p><br>
</p>
<p>Notwithstanding Rob's assertion below (about ea11), the above
looks a tad off-set clockwise-ward (looking up at it), relative to
the quad legs. Of course, I'm not looking straight up from the
center of the dish, and it was best-efforts aligning myself with
the quad legs (and the sun was bright!). I'm not sure this
looks like as much as 10 deg (as Rick reports), but it is easily 5
deg, I think, and Rick's measurement would be consistent with ea01
being at -5 deg (and Rob's assertion that ea01 is a bad
reference), and most of the others in his table would be closer to
zero. Of course, there are 20+ other antennas that are
well-aligned with ea01...<br>
</p>
<p><br>
</p>
<p>Cheers,</p>
<p>George</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 9/18/24 11:43, Rob Long via
evlatests wrote:<br>
</div>
<blockquote type="cite" cite="mid:ceebb308-49af-4353-a85b-c10a13022854@nrao.edu">
<p>Hi Rick,</p>
<p><br>
</p>
<p>It looks like our main dipole culprit is ea01. The dipole
itself is not orthogonal (elements twisted) and we are going to
have to get with the mechanics to get it removed so we can align
it or install the spare.</p>
<p><br>
</p>
<p>ea11 (on the other hand) looks to be aligned well (if you
wanted to use it as a reference).</p>
<p><br>
</p>
<p>Rob<br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 9/10/2024 3:43 PM, Rick Perley via
evlatests wrote:<br>
</div>
<blockquote type="cite" cite="mid:MN6PR14MB71472397D118DFA0FBCAB96BD79A2@MN6PR14MB7147.namprd14.prod.outlook.com">
<style type="text/css" style="display:none;">P {margin-top:0;margin-bottom:0;}</style>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Ther results of a polarization calibration of a recent P-band
dataset (obtained via VLITE) indicate a significant number of
antennas with apparently misaligned feeds. </div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
As this was a VLITE database, there were only 18 antennas
included, one of which was out of service. For the seventeen
others, the calibration shows seven antennas misaligned by
more than 5 degrees w.r.t. the reference dipole (ea01). They
are:</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea17 5.7 degrees</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea07 8.6</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea11 10.3</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea20 5.7</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea23 5.2</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea27 8.0</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
ea21 8.6</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
It is my impression (but I do not have the data in hand to
prove it) that this is worse than what was seen a few years
ago. </div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
These misorientations should be easily visible from the
antenna surface. It would be good to know if visual
inspection agrees with the observations. </div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Rick</div>
<br>
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