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This sounds like it might be cracked waveguide flange or slight
misalignment due to loosed screws, specifically on the waveguide
corrugated phase shifter. Either could result in a trapped
higher-order mode resonance, which may explain the spike in cross
pol. Fortunately it's a fairly straightforward problem to fix in the
lab, if this turns out to be the culprit.<br>
<br>
-Wes <br>
<br>
<div class="moz-cite-prefix">On 3/28/2025 10:33 AM, Rick Perley via
evlatests wrote:<br>
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<blockquote type="cite" cite="mid:DM4PR14MB71322A2905C5C583FDCC4B94D7A02@DM4PR14MB7132.namprd14.prod.outlook.com">
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<div>Two antennas have bad polarizers at Ka-band.</div>
<div class="elementToProof"><br>
</div>
<div class="elementToProof">By far the worst is ea16: There is a
resonance-looking maximum in cross polarization, reaching 60%
(!!!) at 31.74 GHz. </div>
<div class="elementToProof"><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);">
Similar, but much less severe, is ea18 — 15% at 31.93 GHz. </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>
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<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>
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