Differences

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--- evn:supportscientists:problems [2019/05/17 11:50] – [List of problems found] benito
+++ evn:supportscientists:problems [2020/02/05 10:13] (current) – nair
@@ Line 3: / Line 3: @@
 === Active general issues ===
+None\\
-**Jodrell Bank**: Wiggles in LCP across the band since ~2017 session 2 from unknown origin. It is visible in NMEs or spectral line experiments, although in continuum ones the wiggles are smeared out and only a larger scatter is visible.
-Last checks from Eskil point to: "One of the receiver boards in one optical-to-RF converter used for Mk2 VLBI seems to be suboptimal. With very high input power, it works, but when decreasing the power to usual or weaker than normal observing level, the jagged bandpass appears. We'll investigate buying a replacement model. In the mean time, we'll use the identical Lovell hardware which appears to suffer less from this problem."
+===== 2019 Session 3 =====
+=== L - Band ===
+**Jodrell Bank (Lovell)**:
+There is no ANTABFS files produced from station for any of the Lovell L band observations, due to a new
+source of RFI identified at Jodrell Bank which it appears has had very deleterious effects on all the Lovell L band observations for this session. This new RFI is approximately 30 dB above the noise and 20 Mega Hertz wide, spanning 1472 - 1492 Mega Hertz.
+The RFI is believed to be for a 4G+ mobile phone service which will bridge the gap between 4G and 5G. It is thought that the signal provides coverage to the Manchester metropolitan area, and this is seen at Pickmere and Darnall too.
+This signal was first observed in September / October 2019 and they are still devising methods to mitigate its effects. \\
+===== 2019 Session 2 =====
+=== L - Band ===
+**Tianma**: Recorded linear polarization (eg.user experiments - EG100C-D and EH036A-F).\\
-Solved for 2019 Session 2.
 ===== 2019 Session 1 =====
-**Urumqi**: No ANTAB files produced (invalid TPI values recorded for all experiments).
+**Urumqi**: No ANTAB files produced (invalid TPI values recorded for all experiments).\\
-**Tianma**: In this session they have fixed the high leakage observed in the last year.
+**Tianma**: In this session they have fixed the high leakage observed in the last year.\\
+**Jodrell Bank**: Wiggles in LCP across the band since ~2017 session 2 from unknown origin. It is visible in NMEs or spectral line experiments, although in continuum ones the wiggles are smeared out and only a larger scatter is visible.
+Last checks from Eskil point to: "One of the receiver boards in one optical-to-RF converter used for Mk2 VLBI seems to be suboptimal. With very high input power, it works, but when decreasing the power to usual or weaker than normal observing level, the jagged bandpass appears. We'll investigate buying a replacement model. In the mean time, we'll use the identical Lovell hardware which appears to suffer less from this problem."
+**Solved for 2019 Session 2.**
@@ Line 18: / Line 36: @@
 **Sardinia**: LL signal in Subband 8 much lower than RR signal.\\
 **Svetloe**: LCP is broken (at least in the NME).\\
-**Urumqi**: recorded linear polarization (at least in the NME).\\
+**Urumqi**: recorded linear polarization (in the NME and also in the user experiments, eg. EP106E, EP106F and EP106G).\\
-**Tianma**: recorded linear polarization (at least in the NME).
+**Tianma**: recorded linear polarization (in the NME and also in the user experiments, eg. EP106F and EP106G).
 === C - band ===
@@ Line 29: / Line 47: @@
 **KVN**: high invalid data percentage (~7%).\\
 **Sardinia**: No LL signal in subband 7 (and bad sampler stats there too).\\
+=== M - band ===
+**Torun**: large cross hand amplitude noticed (~30%).\\
 ===== 2018 Session 3 =====