[evlatests] Bad polarizers at Ka-band {External}

[Wes Grammer]

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.

-Wes

On 3/28/2025 10:33 AM, Rick Perley via evlatests wrote:
> Two antennas have bad polarizers at Ka-band.
>
> By far the worst is ea16:  There is a resonance-looking maximum in 
> cross polarization, reaching 60% (!!!) at 31.74 GHz.
>
> Similar, but much less severe, is ea18 — 15% at 31.93 GHz.
>
> Rick
>
>
> _______________________________________________
> evlatests mailing list
> evlatests at listmgr.nrao.edu
> https://listmgr.nrao.edu/mailman/listinfo/evlatests
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listmgr.nrao.edu/pipermail/evlatests/attachments/20250328/821c6e87/attachment.html>