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Emmanuel, given how narrowband and sharp the suckouts are, they may
be from mode conversion happening in the OMT. There's a variety of
possible causes, but one that's likely is a slight misalignment of
the square waveguide port on the OMT with the thermal transition.
I'll ask Dan to make a note of the receiver serial number, so when
we have some time in the future we can look into it.<br>
<br>
-Wes<br>
<br>
<div class="moz-cite-prefix">On 1/14/2014 10:21 AM, Emmanuel Momjian
wrote:<br>
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<div>Antenna ea01 at L-band is showing two suckouts or
spectral dips in its bandpass at 1358.1 and 1360.9 MHz and
in both polarizations (see attached for an example; the two
curves are of the two polarizations). I have seen these in
various L-band data sets taken during the past two months.<br>
<br>
</div>
The dips seem to be receiver related features. They are not
variable, and are calibrating out very well.<br>
<br>
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<div>No other antenna is showing these two features.<br>
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<div><br>
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Emmanuel<br>
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