<font face="Verdana, Arial, Helvetica" size="2">Eskil Varenius updated #16009<br />
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FRING FRNSRC: MIN FFT IN FREQ REQUESTED 1003040 MAX ALLOWED 262144<br />
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<div style="margin-left: 40px;">Ticket ID: 16009</div>
<div style="margin-left: 40px;">URL: <a href="https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/16009">https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/16009</a></div>
<div style="margin-left: 40px;">Name: Eskil Varenius</div>
<div style="margin-left: 40px;">Email address: <a href="mailto:varenius@chalmers.se">varenius@chalmers.se</a></div>
<div style="margin-left: 40px;">Creator: User</div>
<div style="margin-left: 40px;">Department: AIPS Data Reduction</div>
<div style="margin-left: 40px;">Staff (Owner): -- Unassigned --</div>
<div style="margin-left: 40px;">Type: Issue</div>
<div style="margin-left: 40px;">Status: Open</div>
<div style="margin-left: 40px;">Priority: Default</div>
<div style="margin-left: 40px;">SLA: NRAO E2E</div>
<div style="margin-left: 40px;">Template group: Default</div>
<div style="margin-left: 40px;">Created: 03 April 2020 12:52 PM</div>
<div style="margin-left: 40px;">Updated: 07 April 2020 12:07 PM</div>
<div style="margin-left: 40px;">Resolution due: 29 December 2022 12:00 AM (995d 11h 52m)</div>
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<p>Hi Eric,</p>
<p>Thank you very much for the quick reply. Yes, the frequency setup is a mess. This is an unusual experiment, which I was not involved in before getting some data to look at. After iterating with colleagues we will probably re-correlate these data with different/smaller bands to avoid the overlap issues. But, I still wanted to try your good advice to learn if it works or not. </p>
<p>I first tried NOIFS on the S/X data, but it refused with <br />"FNDFRQ: AXIS11 CENTER FREQUENCY NOT ON CHANNEL"</p>
<p><br />I then did UVCOP to slice out the interesting X-bands, and reduce the overlap, which resulted in this frequency setup:</p>
<p><code></code><code></code></p>
<pre>Frequency Table summary uses reference channel 9.00<br />FQID IF# Freq(GHz) BW(kHz) Ch.Sep(kHz) Sideband Bandcode<br /> 1 1 8.21091188 2125.0000 125.0000 1<br /> 2 8.21491188 2125.0000 125.0000 1<br /> 3 8.25491188 2125.0000 125.0000 1<br /> 4 8.45067188 2125.0000 125.0000 1<br /> 5 8.46607188 2125.0000 125.0000 1<br /> 6 8.46992188 2125.0000 125.0000 1<br /> 7 8.47377188 2125.0000 125.0000 1<br /> 8 8.48902188 2125.0000 125.0000 1<code><br /></code></pre>
<p>However, NOIFS still fail, now with message</p>
<p>FNDFRQ: AXIS 5 CENTER FREQUENCY NOT ON CHANNEL</p>
<p>NOIFs work for bif=1; eif=4 and bif=6;eif 8. But if I involve IF5 in any way, it fails. I was under the impression that NOIFs would deal with this tiny overlap? Perhaps it is because the IFs are not regularly spaced?</p>
<p>Re COVID-19: I hope you and your colleagues are safe and well.</p>
<p>Kind regards</p>
<p>Eskil</p>
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