In addition to what Ken has already listed, note that the stress test results do not generate any evlatests email traffic, because problems found through the stress tests get reported by the operators through maintenance tickets.<div>
</div><div><br></div><div>Regarding some of the issues that were reported by Rick:</div><div><br></div><div><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>2) S-band: No fringes or PDif from ea03 -- presumably, the receiver </span><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">is not yet in? </span></div>
<div><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><br></span></div><div style="font-family:arial,helvetica,sans-serif;color:rgb(0,0,0)"><font><span>S-band did not have receiver until yesterday. The stress test of last night shows ea03 working fine.<br>
</span></font></div>
<div><font><span style="color:rgb(34,34,34);font-family:arial,sans-serif"></span></font></div><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><div><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 3) C-band: All antennas fringe. ea14 gives a negative, or </span><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">extremely weak, PDif on all IFs.</span></div>
<div><br></div><div>ea14 seems to be OK based on the amplitude gain and Tsys values in last night's test.<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 4) X-band: No fringes from ea20. PDif = 0 from ea02 and ea20.</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>Both antennas show healthy PSum. ea14 has very low PDif, but o.k. PSum.</span></div><div><br></div><div>ea20 did not have a receiver for a while. The stress test of last night shows it has one now, and it is working as expected. Also, its Tsys values are well behaved. ea02, on the other hand, has extremely bad Tsys values (reflecting something is wrong in its switched power system).<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 5) Ku-band: No fringes from ea23, but PSum and PDif both normal.</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>ea10 is showing large gain changes from scan to scan (0.7 dB). All</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>others o.k.</span></div><div><br></div><div>ea23 looks OK based on last night's test (it has fringes, but its Tsys is ~50% higher). ea10's issue, whatever it is, cannot be revealed from a single scan per band stress test.<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 6) K-band: No fringes from ea23, and PDif is very small (Tsys</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>claimed to be 500K). Ea07 has system temeprature of about 300K. All</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>others o.k.</span></div><div><br></div><div>ea23 and ea07 are OK as seen in last night's test. However, ea28 had a serious failure (Jerry just reported the problem and its fix)<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 7) Ka-band: No fringes from ea23, and PDif equal zero on all IFs.</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>(Or, Tsys >1000 K). All others o.k.</span></div><div><br></div><div>This was OK last night.<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> 8) Q-band: No fringes from ea 23 on IFs B and D (and PDif = 0).</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">>Fringes seen on IFs A and C.</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> ea08 gives zero PDif on all IFs.</span><br style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">
<span style="color:rgb(34,34,34);font-size:12.727272033691406px;font-family:arial,sans-serif">> Very high Tsys (> 200K) on ea 7 and ea18.</span></div><div><br></div>
<div>While ea18 is OK in last night's test, ea07 has Tsys values that are 2-3 times worse compared to other antennas. ea18 seems to have a serious problem in its switched power system.</div><div><br></div><div>In conclusion, the stress tests do find issues, and the operators take care of reporting them through maintenance tickets based on the detailed instructions we have provided them. Also, the design of the stress test (to have it done within less than 30 minutes, and the fact that it is run one day a week, and twice on that same day: before and after the maintenance) does not allow it to reveal every single issue (especially some transient ones).</div>
<div><br></div><div>Emmanuel</div><div><br></div>
<div><div><div><br><br></div><div><div class="gmail_quote">On Wed, Mar 6, 2013 at 10:24 PM, Bryan Butler <span dir="ltr"><<a href="mailto:bbutler@nrao.edu" target="_blank">bbutler@nrao.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
i'm curious why our normal stress test isn't finding these issues? i<br>
thought that was the whole point of those observations.<br>
<br>
-bryan<br>
<br>
<br>
Rick Perley wrote, On 3/6/13 12:00 :<br>
<div><div>> From the short test, preparing for the 'flux densities', I find:<br>
><br>
> 1) L-band: All antennas o.k., all PDifs are plausible.<br>
><br>
> 2) S-band: No fringes or PDif from ea03 -- presumably, the receiver<br>
> is not yet in? ea06, on IF 'A' gives a sinusoidally varying PDif of 20%<br>
> amplitude, and 1 minute period. (It has always done this).<br>
><br>
> 3) C-band: All antennas fringe. ea14 gives a negative, or<br>
> extremely weak, PDif on all IFs.<br>
><br>
> 4) X-band: No fringes from ea20. PDif = 0 from ea02 and ea20.<br>
> Both antennas show healthy PSum. ea14 has very low PDif, but o.k. PSum.<br>
><br>
> 5) Ku-band: No fringes from ea23, but PSum and PDif both normal.<br>
> ea10 is showing large gain changes from scan to scan (0.7 dB). All<br>
> others o.k.<br>
><br>
> 6) K-band: No fringes from ea23, and PDif is very small (Tsys<br>
> claimed to be 500K). Ea07 has system temeprature of about 300K. All<br>
> others o.k.<br>
><br>
> 7) Ka-band: No fringes from ea23, and PDif equal zero on all IFs.<br>
> (Or, Tsys >1000 K). All others o.k.<br>
><br>
> 8) Q-band: No fringes from ea 23 on IFs B and D (and PDif = 0).<br>
> Fringes seen on IFs A and C.<br>
> ea08 gives zero PDif on all IFs.<br>
> Very high Tsys (> 200K) on ea 7 and ea18.<br>
><br>
> The lack of fringes from ea23 for Ku, K, Ka and Q band seems to<br>
> indicate a problem with the UX downconverter<br>
><br>
><br>
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