Summary of the GMVA Session, Sep. 28 - Oct. 2 2017 ================================================== Participating stations: Effelsberg, Pico, Yebes, Onsala, Metsahovi, VLBA, GBT, 3xKVN General Summary: ================ Initial fringe test in Europe (f172a) showed fringes between Eb, On, Mh, Ys. Effelsberg records with DBBC (Ef) and RDBE (Eb). Eb, On, Mh, Ys record on Flexbuff. Ef (DBBC) was wrong configured. However after restart before c172a fringes were found on c172b a few hours later. Due to bad weather at Pico, ad-hoc fringe test was performed during the first 2 scans of c172b. Fringes between Ef/Eb and PV then also found. VLBA: PT-MK often taken out because of USNO observing, 1.5 hrs per day lost FD communications and power problems, most likely lost for large fraction of time total loss: 6.3% c172a 0.0% c172b 16.4% c172c GBT: no pointing, for most of the session, no Tsys for at least half of c172c =============== Some notes from e-mail during observations: Sep 28: EB overcast PV bad weather, no obs. Ys, On, Mh: observing Sep 29: PV: bad synthesizer, replaced EB: cloudy, pointing problems until 12 UT, later better PV: resumes for c172b Sep 30: EB: heavy rain all day, improved after 22 UT PV: very cloudy Oct 01: EB: clear during night, clouds after 17 UT, rain after 21 UT PV: overcast, after 17 UT 10mm H20 Oct 02: ALMA mode test (Europe only) EB: all good PV: ok Ys: screwed, did not edit the schedule, no Operator Mh: probabaly ok On: probabaly ok =============== Notes from Onsala: Here it is a short summary of the GMVA observations at Onsala 1. F172A Fringes to both DBBC2#1 (O6, testing one) and DBBC2#2 (On) with a similar SNR. No report of polarisation swap. So, the polarisation should be OK. 2. C172A, B, C Onsala used only DBBC2#2 and observed all of these scientific experiments with a few minor issues. (1) A tiny data package loss at the scan beginning. This Flexbuff recording problem was happened in the first day and fully solved at 272d8h20m by changing the default net_protocol setup. This was triggered by the upgrade of Flexbuff OS and kernel. (2) ~10s data with bad sampler statistics at the scan beginning. This is related to PFB V16 and Onsala Chopper wheel calibration. I discussed it with Sven. He told me that full_auto mode has an internal fixed interval of 10s. At Onsala, the hot load was in and out to measure Tsys in preob. This hot load will add 300 K to the system. When the hot load is out at the scan beginning, the large power jump will cause bad sampler statistics if the full_auto mode can not adjust the output fast enough. This might explain my earlier bad experiences that our system frequently went to overflow/underflow and requested a restart when the weather was bad, i.e. large power fluctuation. So, I suggest to flag out the first 10s data in the post data reduction. 3. T172D* In the three ALMA mode tests at midnight, our antenna was not on-source in the first one. So, do not fetch the data of T172D1. The rest two parts should be fine. 4. Local wether Onsala had quite good wether in most of the observations time with Tsys*~200 K. The only poor part was 274d8h — 274d18h. During the time range, Onsala had rain with a Tsys* of 300 –– 5000 K =============== Notes from GBT: The GBT ran the 2 projects C172B (GMVA17B-299) and C172C (GMVA17B_297). C172B ran smoothly on Sept 29, although many of the pointing scans were unsucessful due to observing in the daytime. The calibration wheel of the 86 GHz receiver failed and got stuck in the circular polarization position at about 23:40 UT on Sept 30. Since the wheel did not move, we could not do Tsys calibrations. We will have Tsys for the first 24 hours of C172C, but will be unable to provide Tsys for the 2nd 24 hours. On the other hand, the weather has been clear for both experiments, and nighttime Tsys was sometimes down to 80-90 K. When the cal wheel got stuck, the operator kept the script going by manually selecting position 2 (the circular pol position) in the receiver Cleo screen, every time the script tried to do a cal sequence. But this meant that the automatic processing of pointing scans was not working because the software was expecting cal sequences, which were not happening. On Sunday morning I remembered an option in the "VLBI.conf" config file to disable cal sequences. This was done about noon on Sunday, so the script did not try to do any cal sequences, and the processing of pointing scans worked. The operator still had to manually select position 2 every time there was a pointing scan, because the default pointing configuration called for the "observing" position. Tsys info on: https://safe.nrao.edu/wiki/bin/view/GB/Observing/WbandVLBACal/C172 =============== Logs from VLBA: VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C172A Observer: Krichbaum, T. Project type: VLBA Obs filename: c172acrd.* Date/Day: 2017SEP29/272 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Betty Ragan. Vclock, gps delta, UT1-UTC all check OK. 0057 Begin at all sites excpet MK. 0057-1357 %OV 3mm tsys high on RCP. FE 25 195 0118 Begin at MK. 0229-0753 %LA raining. 0339-0517 *PT,MK removed to run daily USNO observation. SCH 200 196 0411 %FD raining. 0545 New operator is Alan Kerr 0708-1357 %FD communications down. data should be good. NET There will be no monitor data during this period. 0820-1357 %MK windy. occasional 35mph wind caution warnings WEA 1035-1357 %LA precipitation 1343 New Operator: Paul Padilla 1357 End. Downtime Summary: Total downtime : 391 min Percentage downtime of observing: 6.3% Average downtime per hour : 3.8 min Total scheduled observing time (# Antennas): 6240 min (8) =============== VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C172B Observer: Krichbaum, T. Project type: OTHER Obs filename: c172bcrd.* Date/Day: 2017SEP29/272 Ants Scheduled: NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Paul Padilla UT1-UTC: 0.32, VClock: -0.015, GPS delta: -8.3 1407 Begin at all sites except nl 1407-2225 %FD communications are down. Antenna should still COMM be pointed as the previous project ended just a few minutes before this project began. There will be no monitor data for FD during the internet outage. 1418 NL joins 2225 End. Downtime Summary: Total downtime : 0 min Percentage downtime of observing: 0.0% Average downtime per hour : 0.0 min Total scheduled observing time (# Antennas): 3984 min (8) =============== VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C172C Observer: Krichbaum, T. Project type: OTHER Obs filename: c172ccrd.* Date/Day: 2017SEP29/272 Ants Scheduled: NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Betty Ragan. Vclock, gps delta, UT1-UTC all check OK. 2230 Begin at GB. 2237 Begin at VlBA sites, except MK. 2237-2231 BR Q-band RCP Tsys higher than LCP. 2237-1856 *FD communications are out. Unable to point COMM 100 2659 antenna. 2237-2231 *OV has high 3mm RCP tsys. FE 25 718 0000 Date is 2017SEP30/273. 0130 Begin at MK. 0430-0437 *NL has TimestampSyncError alert on DBE 1. TIME 100 7 0545 New operator is Alan Kerr 0624-0802 *PT,MK out for daily USNO observation. SCH 200 196 1345 Operator is A. Sowinski. 0000 Date is 2017OCT01/274. 0012 %LA raining. 0143 New Operator: Karlee Radford 0224-0319 *PT,MK out for daily USNO run. SCH 200 110 1340 Operator is A. Sowinski. 1805-1845 All sites: vls crashed (or netmon or vlget). Unable to monitor certain systems (ACU and FRM most critically). 1853 FD communications up. Site okay. Pointing antenna. 1856-2231 FD W-band LCP Tsys higher than RCP. 1904-2023 *KP Commercial power outage. Antenna stowed. COM 100 79 2231 End. Downtime Summary: Total downtime : 3769 min Percentage downtime of observing: 16.4% Average downtime per hour : 9.8 min Total scheduled observing time (# Antennas): 23048 min (8) Notes: * = Entries where data was affected. % = Entries where data may have been affected. & = Entries where the site tech was called out. WEA = Weather entries. MF# = Maintenance form or major downtime category associated with a problem. %AD = The percentage of an antenna affected by a problem. AMD = Total antenna-minutes downtime for a problem. Tsys = System Temperature (TP/SP x Tcal/2) ACU = Antenna Control Unit FRM = Focus/Rotation Mount RFI = Radio Frequency Interference VME = Site control computer CB = Circuit Breaker vclock = Program that compares site clock time to a standard.