EVN Technical & Operations Group (TOG) Meeting Friday 24th March 2006 ASTRON, Dwingeloo, the Netherlands Introduction ------------ The EVN TOG held a meeting on 24th March 2006 at ASTRON, Dwingeloo, the Netherlands. Approximately 50 people attended the meeting. The chairman was Alef. Foley outlined local arrangements. Willem Baan welcomed the visitors to Dwingeloo. Alef also welcomed the many new participants and outlined the role of the TOG in keeping the EVN working together, and in transferring expertise and technological developments within the EVN and Global VLBI network. Summary reports and presentations from the meeting are available at: http://www.mpifr-bonn.mpg.de/div/vlbicor/tog_chair/togreps06/ 0. Approval of and additions to agenda -------------------------------------- The agenda was approved, with no additions requested from the participants. 1. Review of action items from last meeting ------------------------------------------- The TOG reviewed action items from the previous meeting. 1. Action: Paragi and Reynolds to verify that the NICT software correlator works for 1 Gbps recording - done 2. Action: Garrington to make the Mk2/Lovell phase referencing technique available as a working process for users - no one from Jodrell was present, but some progress has been made. The action remains open. 3. Action: All stations should look at data regularly with chchk program, use it to locate significant RFI and report the results to Polatidis, and use it to check phase-cal throughout the session - Polatidis has not yet received any RFI information from stations. Baan commented that such information is important not only for scientific reasons but also for spectrum protection. There was some discussion of the importance of RFI reporting. Charlot noted that it is important that PIs are aware of potential RFI problems, and this information should appear in the EVN status table. In summary, stations should report persistent RFI to Polatidis and also to CRAF (Committee on Radio Astronomy Frequencies) representatives (at their own institutes or to ASTRON's Titus Spoelstra). Reynolds commented that autocorrelation plots from the data pipeline at JIVE could additionally be checked for RFI; Campbell added that spectral line experiments are most useful, however the available data may be sparse. Therefore the JIVE pipeline data could be only a supplement to RFI reporting at stations. 4. Action: All stations were encouraged to check amplitude corrections on pipelined experiments available from the JIVE webpage - ongoing action. This is being done regularly at some stations. Alef urged VLBI Friends at all stations to look at pipeline results. 5. Action: Stations were asked to provide detailed Wx and RFI comments in experiment logs - ongoing action. Paragi said that feedback from stations had improved. Temperature, pressure and relative humidity are logged in standard format in the FS log. Linqvist noted that comments are also important to help users and JIVE staff assessing data quality. 6. Action: All stations to continue monitoring Tcal throughout sessions - ongoing action. Reynolds commented that this is still important as Tcal is found to vary. Graham commented that this is especially true at L-band. 7. Action: Reynolds to look at tpidiff for a range of experiments and recommend a suitable time between diode firings. Update SCHED accordingly - the new release of SCHED (which will be available shortly) issues a warning if suitable gaps on source for diode firings are more than 15 minutes apart. Reynolds commented that there is no one number suitable for every experiment, but 15 minutes is a reasonable time between diode firings for most experiments. 8. Action: de Vicente was asked to report on implementation of continuous tpi on VLBA systems - not yet done as antenna at Yebes is not ready yet, but some progress has been made. 9. Action: Stations to produce ANTAB and RXG files within 2 weeks of the end of a session - Reynolds said that the 2 week goal is not met by most stations. Alef asked if is was unreasonable for the stations to submit calibration data within 2 weeks. Foley responded that 2 weeks is not enough if inspection of the data is needed, and other Friends agreed. One possibility is that first "quick and dirty" numbers could be made available, then improved data submitted when ready. This discussion led to a new action: Action Item: Alef to request feedback from users as to whether they would prefer calibration data in two stages (first quick preliminary and then final numbers later) or whether they would prefer to wait longer and have high quality calibration data to start with. This is to be presented at the EVN users meeting in Torun. 10. Action: Stations must regularly check for Mk5 software updates and ensure the software matches the appropriate FS release - not relevant as there has been no new releases since the last TOG meeting. There was some discussion of support for Mk5 software/OS problems - to be followed up in the main agenda 11. Action: All stations are to provide information to Alef on disk space currently purchased and future plans for buying disk packs - mostly done. Foley still to send Wb information to Alef. 12. Action: All stations to forward FS error log files to Himwich and include details of what the FS was doing when the crash occurred - action remains open. There have been no crashes reported since the last TOG meeting. 13. Action: All stations to provide to Himwich detailed descriptions of all bugs encountered in the FS - previous action item should include this 14. Action: Stations to provide frequency agility information to Reynolds - see following item 15. Action: Reynolds and Walker to incorporate frequency agility information in SCHED - not done yet. A request will be sent to stations to send frequency agility information when SCHED has been made ready to incorporate this. 16. Action: Alef to ask Polatidis to update the EVN status table with new/additional frequency agility information - pending previous action 17. Action: Burgess to maintain Mk5/disk spare parts list - Burgess not present, however Ritakari remarked that the list is on the website maintained by Burgess at http://newton.jb.man.ac.uk/ 18. Action: Medicina station to look into polarization leakage at 22 GHz - done/no longer an issue. (Possible high leakage was reported in N05K1 NME report but subsequent data was found to be OK.) 19. Action: All stations to look at NME reports sent by JIVE - ongoing action. Many VLBI Friends indicated they look at NME reports regularly. 20. Action: Alef to send email to Alan Whitney regarding Mk5 communications problems - done 21. Action: Torun station to fix problem with BBC#3 - done 22. Action: Stations with a VLBA terminal were asked to check whether they have an extender cable to loan to Torun for use in testing their rack (for BBC#3 problem) - this may be still required Action Item: Whitney to find out whether spare cable is available at Haystack. 23. Action: Alef to send information regarding monitoring of scan_check during recording - clarification needed. This was regarding how to check for discrepancies in scan values and flag problems in the display window. 24. Action: Alef to communicate to scheduler that ftp tests should as a rule be scheduled 2 days in advance of each session, and NMEs are to be scheduled at the beginning of each session - done 25. Action: Himwich, Graham and Gunn are to include Graham's monitoring software with future distributions of the Field System - action remains for future FS distribution 26. Action: Gunn to send email before each session when the final versions of all schedules are ready for download - Gunn not present - will return to this issue 27. Action: Reynolds is to provide statistics on pipeline amplitude calibration including the sign of amplitude errors - done. Reynolds to demonstrate this later 28. Action: Reynolds is to request feedback re. amplitude calibration from spectral line users at JIVE in order to assess results of different calibration methods - not done yet 29. Action: Alef to ask CBD to revise correlation priorities in the 1Gbps era - done (CBD already saw this as an obvious requirement) 30. Action: Alef to send the specifications of foam for shipping disk-packs to EVNtech - done. This was in order to look for cheaper alternatives to the foam from Conduant. Schonewille reported that JIVE has found another supplier of foam. Alef commented that this had somewhat different specs. JIVE hasn't yet seen any damaged boxes, although one disk pack sent from Urumqi arrived with a bent chassis. Action Item: All VLBI Friends to check that Mk5 modules are placed squarely on a flat surface when received, otherwise connectors are easily damaged when bent 8-packs get inserted in Mark 5 units. 31. Action: All stations are requested to try to run the FS diagnostic tests for the October 2005 session and investigate the results - ongoing action. Lindqvist and other Friends who ran the tests commented that they were very useful. 32. Action: Reynolds is to look into scheduling of Lovell+MkII for phase-referencing - not done yet 33. Action: Paragi is requested to arrange a test of the Jodrell MkII/Lovell phase-referencing technique for a C-band NME in the next session - still to be done along with previous action 34. Action: Reynolds is to work with Rene Vermeulen on the guide for polarization calibration using WSRT local interferometry data - discussed, but not done yet - will return to this issue. Foley has a list of suitable polarization calibration sources from Denise Gabuzda for WSRT observations. 35. Action: Gunn is to present an inventory and status report on Mk5/disk spare parts at the next TOG meeting - Gunn not present 36. Action: Himwich to contact Tuccari regarding the DBBC interface - they are in contact. Some details are still to be worked out. 37. Action: Alef to establish contact with Brian Corey regarding DBBCs - not done yet 2. Summaries from mini-workshop ------------------------------- In general feedback from the workshop was positive. Whitney found the amount of time allocated appropriate to cover basics of the Mk5 system. A number of participants commented that they found the Mk5 course very useful. Whitney suggested that because of the mixed levels of expertise, it may be good for future workshops to group participants according to their experience, but this is not always easy to arrange. Another comment was that making presentations available on the web is particularly important for TOG members who were not able to attend the workshop. 3. Reliability/Performance -------------------------- Paragi presented NME results, and explained the EVN Reliability Indicator (ERI), which is the fraction of 'good' visibilities out of the total number of expected visibilities for an experiment. Paragi's report is available on the web. There were a few responses to the report from individual stations. Foley reported that Westerbork now has its own repaired Mk5 unit back. Regarding the GB052 feedback from Medicina, no fringes were found at Socorro. It was suggested that the tape rate may have been too high, perhaps due to a faulty servo on the capstan motor. Torun did not have enough disks to observe GB055B because some of their disks were found to be bad. Some investigation has been done into the lack of fringes for VC#8 at Torun seen in fringe tests and NMEs from session 2006/1, but so far they have been unable to find the problem. It was noted that phase-cal should always be checked to assist with diagnosis of problem channels. Urumqi plans to get a new K-band receiver. An Tao reported that Shanghai noted high Tsys at K-band but do not yet know the origin of their problem - this will be investigated. Not only were no fringes found to Sh at K-band in session 3/2005, but no maser line was detected in the autocorrelations where it was clearly seen at the other stations. Action Item: JIVE support scientists to give detailed feedback to Sh regarding problems with the K-band data from session 3/2005. Himwich reported that automated ftp is now implemented, just waiting for the new release of the Field System. Alef requested input from stations regarding ftp tests this year. Alef commented that stations have had fewer "human" errors in recent sessions - problems are usually due to hardware failures, software and schedule problems. Training of people at telescopes has improved, and rapid feedback from the ftp fringe tests has helped in a number of cases. Paragi summarised what to look for in fringe test feedback. There was some discussion of possible improvements to the feedback. Action Item: Paragi to implement labelling of fringe plots with sky frequency and sideband. Alef requested that a summary of each station's performance, including station feedback and ERI for each experiment, be presented at the next TOG meeting in the form of a table. There was some discussion of the process of schedule submission, checking and downloading, in particular how to avoid stations observing different versions of the schedule. The current standard procedure is that PIs deposit schedules on vlbeer 3 weeks before the start of the session. The following week is set aside for the schedules to be checked at JIVE. Stations should not download the schedules until after that week. At a previous TOG meeting Gunn volunteered to perform some additional checks on schedules and then send email to prompt Friends to download schedules, but this email was not seen for the last session. PIs are supposed to email all Friends when a new version of the schedule is uploaded after the deadline, but some problems still occur due to late submission and lack of communication, or incorrect version numbers in schedules. The PI is ultimately responsible for observational failures resulting from such errors, however if some problems can be prevented with small changes to the procedure, this is of course desirable. It was suggested that a separate area be created on vlbeer, from which stations should download schedules after they have been checked. This is be trialled in the next session. An email will be sent if there are any schedule updates after the deadline (i.e. less than 2 weeks before the start of the session). Action Item: Orlati to ask the vlbeer maintainer (Mauro Nanni) to create a subdirectory called e.g. 'latest' or 'checked' for stations to download schedules from. Alef, Campbell, Foley and Gunn to distribute an email to all stations detailing the new procedure. In response to suggestions that PIs may not need to know about this, Reynolds argued that it is important to make PIs aware of the new procedure even though the schedule submission procedure will remain the same for them. Alef asked if there had been any problems with phase-cal checks. No problems were reported but noone has tried decoder checks. Foley mentioned that he checks phase-cal using a filter and oscilloscope. Alef reiterated that all stations should monitor phase-cal throughout sessions. Sampler statistics are much improved recently. Although there have been no recent problems it is important for stations to keep checking the sampler stats. Bad sampler stats may indicate power supply problems. If stations do not have the time to perform the recommended checks, they should contact Alef. Reynolds reported that polarization calibration using Westerbork local interferometry data to calibrate the EVPA was done in one experiment from session 2/2005 and evidently worked well. Documentation on the procedure is still needed. Regarding the Lovell-MK2 problems with interchange, Romney remarked that the confusion at Socorro for GM057A was a one-time failure due to operators not being aware of the different telescopes (out of "institutional memory"). Inspection of NRAO 'sniffer plots' for checking station performance in Global experiments correlated at Socorro was discussed. Stations could email concerns related to these plots to analysts@nrao.edu (the analysts do not generally see it as useful to check EVN session feedback). Romney is to provide the URL and give a short demonstration of how to interpret these plots in the afternoon. 4. Amplitude Calibration ------------------------ Alef reported that the CBD is concerned about lack of improvement with respect to timely and reliable calibration data. Reynolds gave a report on amplitude calibration. Both the written report and slides from the presentation are available on the web. In response to an action item of the previous TOG meeting, a statistical summary of amplitude calibration factors (from selfcal on calibration sources) is now available on the (recent) pipeline plots pages. For strong, compact sources with many scans these numbers are generally a good indicator of calibration accuracy. However sometimes this may not be the case, if a source is highly resolved or there is little data. Where there are real calibration problems in a particular experiment, i.e. large deviations in amplitude correction factors on good calibration sources, then feedback is needed from the station regarding any known problems. This was an action item on the CBD but seems to have not been fed back to all VLBI Friends. Action Item: Reynolds to fix the problems with ANTABFS for VLBA racks. Reynolds noted that timely submission of calibration data is now becoming even more important. Mark Kettenis at JIVE is implementing calibration transfer, so that calibration tables will be attached to correlated data before it is distributed to PIs. The "Extended ANTAB" format has been defined for everyone to use in future. Most stations now produce their own ANTAB files, including Urumqi for the first time last session. Wb, Ef and Ar use their own scripts. Graham summarised calibration problems. His notes are available on the web. The K-band "Chopper Wheel" calibration method at Onsala shows promising results but is not possible to implement at all stations due to hardware requirements. Regarding the opacity correction in gnplt, feedback from PIs on what they want would be useful, also VLBA practise is important. General wisdom dictates that at frequencies below 15 GHz the gain curve includes average atmospheric absorption (independent of seasonal changes). At mm wavelengths opacity is much more significant. An average atmospheric absorption could be included, but would in general not be sufficient. More clarification needed. Action Item: Graham, Lindqvist to form a small group to discuss via email opacity corrections at high frequencies, and prepare a document to present at the next TOG meeting. Action Item: Alef to contact Phil Diamond regarding calibration of Cambridge data. Some stations think we need a Tiger Team for calibration. Alef will propose this to the CBD. Provision of Effelsberg single dish fluxes was also discussed at the CBD meeting. Historically these have been provided. Polatidis said that these could be provided on a "best-effort" basis, on request from PIs. The accuracy depends on many factors such as the weather, observing frequency (particularly at low frequencies, confusion and extended source structure may be a problem). The PI must leave gaps in the schedule on calibration sources and also should request single dish flux density measurements via email/comments in the schedule. Additionally, periodic gaps are needed to check Effelsberg pointing - this is stated in the PI instructions for all experiments at 6cm and shorter wavelengths. Flux densities from Westerbork local interferometry can be even more useful, and no special scheduling is needed. PIs should send a request to Foley for these data. Flux densities could be provided on the web. There was some discussion of monitoring program for single dish flux densities. Action Item: Graham, Himwich and Lindqvist to solve problem with flux estimates for primary calibrators (Cas A etc.) in FS. Stations are very happy to have the CL sessions for calibration. Alef will pass on this feedback to the scheduler. Romney gave a short demonstration of what to look for in the NRAO 'sniffer plots'. He emphasised that these can sometimes be misleading as they are generated automatically with minimal checks (e.g. antennas may still be slewing) so "don't panic" right away if the plots don't show good data. The URL for the VLBA operational file server is: http://www.vlba.nrao.edu/astro/VOBS/astronomy Mujunen requested that links to all relevant data repositories be put on a single web page. This could include not only the EVN and NRAO archives but also the geodetic repository and plots from the Bonn correlator (useful for mm experiments). Action Item: Alef to include on TOG webpage the collection of URLs where stations can look for experiment feedback. Lisa Harvey-Smith (JIVE webmaster) to add this also to 'VLBI links' on EVN web site. Campbell mentioned that various data products are available at JIVE - "standard plots" showing small amounts of data are available first, then later the more complete pipeline plots are available. In principle, plots made during clock-searching could also be provided. Action Item: Campbell to write a summary of data products available from JIVE. 5. Automatic flagging --------------------- There was little to report on automatic flagging. It is implemented for all stations except Westerbork, for which a script is currently being produced. 6. Mark 5 --------- Whitney reported on the status of Mk5. His report and presentation are available on the web. There was some discussion of availability of VSI connectors and cables. Romney presented results from the pre-meeting on transition and compatibility from Mark 5A -> 5B, held on 23rd March. This issue was discussed two years ago but there has since been some changes. Conclusions from the pre-meeting are summarised in a slide available on the web page. The deployment of Mark 5B is to be decided at the next TOG meeting. It is proposed that Mark 5B first be evaluated at JIVE, then recommendations passed on to stations. Foley commented that Westerbork will be VSI compatible soon when the new digital tied array comes on line, so they would like a Mk5B system as soon as possible. However Szomoru was concerned that the next TOG meeting may be too early for JIVE to properly evaluate the Mark 5B system, as there are a number of implications for the correlator which need to be investigated. Alef asked if there were any new problems with Mark 5. The main problems recently have been with power supplies. Symptoms of a degrading power supply can be confusing. All stations should measure the voltage of the power supply before each session (as described in Dan Smythe's email from 6th February, see also ftp://web.haystack.mit.edu/pub/mark5/sensors.txt). Replacement power supplies are relatively inexpensive. Whitney recommended that stations condition disk packs after shipping, especially those to be used for 1Gbps recording. Conditioning requires a lot of time but is usually done at EVN stations. Action Item: All stations should condition disk packs if time permits, especially those which are to be used for 1Gbps recording. There was discussion of whether the EVN should stop recording on tape. If the EVN stops using tapes, there are possible problems for Global experiments needing to be correlated at Socorro. Possible solutions are to limit the number of stations, to record only a limited number of VLBA stations on disk, or to correlate in multiple passes. Romney suggested that alternatively, perhaps the EVN could provide extra Mk5 units to Socorro - this would require a request to the CBD. The optimal choice seems to be that all Global experiments should be correlated at JIVE, unless there is a good reason (for example, if pulsar gating is needed). If correlation at Socorro is necessary then this could be done in multiple passes if required. Romney objected that it had not yet been determined whether the VLBA correlator could commit enough correlation time to handle the necessary multiple passes. Some change in the correlation policy is implied: currently, the PI can indicate which correlator they would like, but this should be justified in any case. In summary, the TOG proposes to stop recording on tape. Alef is to present this proposal to the CBD. Disposal of tapes and tape drives was briefly discussed. The disk inventory is available on the TOG web page: http://www.mpifr-bonn.mpg.de/div/vlbicor/tog_chair/Diskinventory.pdf All stations should send updates and corrections to Alef. Romney mentioned that the VLBA's disk capacity is currently just over 50% of the EVN's. Action Item: All stations which do both astronomy and geodesy should clearly distinguish between astronomical and geodetic 8-packs and ensure there is no "leakage" into the wrong pool. Campbell reported on disk throughput at JIVE and explained how he calculates disk requirements for each station based on the block schedule. "Normal" EVN stations pay for shipping costs both ways, while JIVE pays for Robledo and Arecibo. As there is a lot of variation in shipping costs, Campbell requested feedback from stations regarding any preferred shipping companies they may have, and whether the disk packs are being sent early enough. The time of shipping is limited to after the publication of the block schedule (at most 6-7 weeks before the beginning of a session). There was some discussion of disk warranty service and repair. Regardless of how this is handled, stations need to have spare disks on hand. A few companies (e.g. Hitachi in Europe) offer replacements under warranty which can be claimed anonymously over the internet, but this is not the case in general. Alef is to send the link to JIVE regarding the Hitachi disks. The JIVE operators had previously suggested that in case of a broken disk, the faulty disk should be replaced with a spare working disk, then the individual faulty disk sent to the station which owns it for repair or replacement under warranty. The owner of the disk should then send a spare back to the station which found the faulty disk. The same policy would apply for NRAO. Romney agreed that this should be OK as long as spare disks were sent back quickly. Romney presented some feedback from the NRAO correlator. In general they are pleased with shipping and data quality from the EVN. There is a problem if stations wait too long to ship disk packs. NRAO tends to correlate in chronological order. Reynolds and Campbell also noted that the "Bologna Rules" for shipping are sometimes being broken with disks, which holds up correlation. Action Item: All stations to ship disk packs as soon as they are full. Romney showed an aluminium plate which the NRAO is using in lieu of covers. The plate screws on and will stop any distortion of disk packs during shipping, while having slots to allow air flow between disks. This saves some weight and NRAO have so far had no problems shipping disks without the covers, however some concerns were raised about using similar plates for the EVN disk packs. It would probably be necessary to wrap the disk packs in plastic to protect the connectors from dust etc., and also the foam is currently sized to fit with the covers on. This will be further investigated at JIVE. We will keep using the covers for now. Romney also showed a new method for labelling disk packs which has been adopted at NRAO, involving a stick-on plastic wallet into which labels can be inserted. These have apparently worked well for the last 9 months. Romney will send information to Alef regarding the supplier of plastic wallets so that the EVN can try them out. Tenkink pointed out that for low data-rate experiments, sometimes more than 10 field labels are needed for a single disk pack, and the current luggage tag labelling method used by the EVN seems more efficient for these. There was some more discussion of labelling of disk packs. It was noted that the 'Conditioning/Problem log' should be placed on the side of the pack which contains the backplane, as this stays with the module whereas the other side may be removed. Action Item: Disk packs should be shipped with one European and one US address on covers so they can be easily returned in case a shipment is lost. It is planned that 1Gbps will become the default for continuum observations as soon as directors buy the remaining disks needed. Whitney reported on the status of SATA and Mk5. PATA disks are still readily available but may not be in future, and SATA is faster. SATA should be interchangeable with PATA in Mk5 units. One option is to place a new connector beside the exising one, meaning a new backplane will be required. So far no suitable connectors have been identified. Available connectors for SATA typically work for only 200-250 connects/removals, compared with several thousand for PATA. 7. Field System --------------- Himwich reviewed the current status of the Field System. His report is available on the web. Action Item: Foley to start a wiki page for FS documentation, which all users can contribute to. There was some discussion of automated periodic firing of the cal diode. Currently the user has to insert suitable scan breaks in the schedule for cal diode firings. The feedback from SCHED has been improved to assist this process, but there are advantages to making it automated. Also, more frequent diode firings give better calibration results. Himwich pointed out, however, that automated cal diode firings in the FS are not readily implemented for some stations. DBBCs offer a superior approach. Alef raised the possibility of support of the FS via RadioNet. Himwich responded that this would be helpful to push along developments. Action Item: Himwich to send message to EVNtech regarding the location of the FS "toolbox" package to install. 8. SCHED Developments --------------------- Reynolds reported on recent developments in SCHED. His presentation is available on the web. The option of tape usage at EVN stations may be removed from the catalogs if tapes are no longer to be used. Stations are requested to send catalog updates to Reynolds. Action Item: Whitney to check the status of the problem with recording stopping, or Mk5 not responding for a period of time, when the key is turned (for changing a module while the other is recording). 9. Comments to/from Scheduler ----------------------------- Porcas recommends changing the format of the status table (the current ascii format is too dense to read easily). Polatidis and others are discussing the new format. A graphical frequency table was suggested. A graphical table of frequency coverage is already available linked from the EVN user guide at http://www.evlbi.org/user_guide/freq_cov.html but this is based on SCHED entries rather than the status table. The scheduler requests that all Friends respond promptly to e-mail. Consider using a generic account which someone else can read when the main VLBI Friend is not there. Please inform JIVE of any updates to contact details. No problems with the block schedule were reported - the current format is OK. 10. Digital BBCs ---------------- Tuccari summarised the EVN DBBC project. Following the mini-workshop an idea was discussed to test the system at the stations in Latvia and the Ukraine. A PC-EVN system could be used for recording (as this is VSI compliant), and a software correlator used for verification. The logistics are still to be decided, but it is expected that observations will be performed during this summer. Ritakari spoke briefly about the IVS working group 'VLBI 2010' report. It is expected that future VLBI will use some technology based on the Allen Telescope Array. ATA memos are available from the UC Berkeley web-site at http://astro.berkeley.edu/ral/ata/memos/ Whitney gave a presentation on the status of the Haystack Digital Backend system. His presentation is available on the web. 11. Spare parts --------------- There was little to report on this topic - the correlators are planning to acquire sufficient spare parts. 12. e-VLBI status ----------------- Szomoru reported on the status of e-VLBI at JIVE. Whitney reported on developments at Haystack. Both presentations are available on the web. Whitney invited all TOG participants to attend the next e-VLBI workshop to be held from 17-20 September this year at Haystack. 13. Station and correlator reports ---------------------------------- Station and correlator reports were not presented orally but are available to read on the web. Alef thanked all contributors for their reports. 14. AOB ------- It was agreed to try out a Wiki for the TOG. Several participants have previous experience with wikis. Foley argued that a wiki would be extremely useful for maintaining documentation, hardware parts lists etc. All users can contribute a small amount rather than one person having to do all the work. 15. Time and Place of Next Meeting ---------------------------------- The next meeting would be held around late November or early December 2006. We have been invited to hold the next TOG meeting at Arecibo, however there may be some difficulties for a number of participants with obtaining visas, and travel costs. Some travel support from RadioNet may be possible if the local organisers can cover other costs (such as the dinner). Noto is a possible alternative location. Action Item: All to send e-mail to Alef within 4 weeks (i.e. by 21 April) regarding the feasibility of attending a TOG meeting at Arecibo. Include any conditions, such as financial support needed. 16. Summary of Action Items --------------------------- Action Item 01: Garrington to make the Mk2/Lovell phase referencing technique available as a working process for users. Action Item 02: All stations should look at data regularly with chchk program, use it to locate significant RFI and report the results to Polatidis and CRAF representatives, and use it to check phase-cal throughout the session. Action Item 03: All stations should look at pipeline results available from the JIVE webpage, in particular amplitude corrections found by selfcal on strong, compact calibrators. Action Item 04: All stations to provide detailed Wx and RFI comments in experiment logs. Action Item 05: All stations to continue monitoring Tcal throughout sessions. Action Item 06: de Vicente to report on implementation of continuous tpi on VLBA systems. Action Item 07: Stations to produce ANTAB and RXG files as soon as possible after the end of a session. Alef to request feedback from users as to whether they would prefer calibration data in two stages (first quick preliminary and then final numbers later) or whether they would prefer to wait longer and have high quality calibration data to start with - feedback to be presented at the EVN users meeting in Torun. Action Item 08: All stations to forward FS error log files to Himwich and include details of what the FS was doing when the crash occurred. Action Item 09: Reynolds and Walker to incorporate frequency agility information in SCHED - stations will be prompted to provide this information. Polatidis then to update the EVN status table with new/additional frequency agility information. Action Item 10: All stations to look at NME reports sent by JIVE. Action Item 11: Whitney to find out whether a spare extender cable is available at Haystack to loan to Torun for testing BBC problems. Action Item 12: Alef to send information regarding monitoring of scan_check during recording - how to check for discrepancies in scan values and flag problems in the display window. Action Item 13: Himwich, Graham and Gunn to include Graham's monitoring software with future distributions of the Field System. Action Item 14: Gunn to send email before each session when the final versions of all schedules are ready for download. Action Item 15: Reynolds to request feedback re. amplitude calibration from spectral line users at JIVE in order to assess results of different calibration methods. Action Item 16: All to check that Mk5 modules are placed squarely on a flat surface when received, otherwise connectors are easily damaged when bent 8-packs get inserted in Mark 5 units. Action Item 17: All stations to try to run the FS diagnostic tests and investigate the results. Action Item 18: Reynolds to look into scheduling of Lovell+MkII for phase-referencing. Action Item 19: Paragi to arrange a test of the Jodrell MkII/Lovell phase-referencing technique for a C-band NME. Action Item 20: Reynolds to work with Rene Vermeulen on the guide for polarization calibration using WSRT local interferometry data. Action Item 21: Gunn to present an inventory and status report on Mk5/disk spare parts at the next TOG meeting. Action Item 22: Alef to establish contact with Brian Corey regarding DBBCs. Action Item 23: JIVE support scientists to give detailed feedback to Shanghai regarding problems with the K-band data from session 3/2005. Action Item 24: Paragi to implement labelling of fringe plots with sky frequency and sideband. Action Item 25: Orlati to ask the vlbeer maintainer (Mauro Nanni) to create a subdirectory called e.g. 'latest' or 'checked' for stations to download schedules from. Alef, Campbell, Foley and Gunn to distribute an email to all stations detailing the new procedure. Action Item 26: Reynolds to fix the problems with ANTABFS for VLBA racks. Action Item 27: Graham, Lindqvist to form a small group to discuss via email opacity corrections at high frequencies, and prepare a document to present at the next TOG meeting. Action Item 28: Alef to contact Phil Diamond regarding calibration of Cambridge data. Action Item 29: Graham, Himwich and Lindqvist to solve problem with flux estimates for primary calibrators (Cas A etc.) in FS. Action Item 30: Alef to include on TOG webpage the collection of URLs where stations can look for experiment feedback. JIVE webmaster (Lisa Harvey-Smith) to add this also to 'VLBI links' on EVN web site. Action Item 31: Campbell to write a summary of data products available from JIVE. Action Item 32: All stations should condition disk packs if time permits, especially those which are to be used for 1Gbps recording. Action Item 33: All stations which do both astronomy and geodesy should clearly distinguish between astronomical and geodetic 8-packs and ensure there is no "leakage" into the wrong pool. Action Item 34: All stations to ship disk packs as soon as they are full. Action Item 35: Disk packs should be shipped with one European and one US address on covers so they can be easily returned in case a shipment is lost. Action Item 36: Foley to start a wiki page for FS documentation, which all users can contribute to. Action Item 37: Himwich to send message to EVNtech regarding the location of the FS "toolbox" package to install. Action Item 38: Whitney to check the status of the problem with recording stopping, or Mk5 not responding for a period of time, when the key is turned (for changing a module while the other is recording). Action Item 39: All to send e-mail to Alef within 4 weeks (i.e. by 21 April) regarding the feasibility of attending a TOG meeting at Arecibo. Include any conditions, such as financial support needed.