public:meetings:2010_04_11_ilto

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision		 Previous revision
public:meetings:2010_04_11_ilto [2011-05-14 07:06] – Harm Munkpublic:meetings:2010_04_11_ilto [2017-03-08 15:27] (current) – external edit 127.0.0.1
Line 13: Line 13:
 All but the Onsala stations have been built. The LBAs at the Jülich station have been installed late in April 2011. All but the Onsala stations have been built. The LBAs at the Jülich station have been installed late in April 2011.
  
-A sixth German station will be built near Bieleveld, probably in 2012.+Funding for sixth German station near Bieleveld is being sought. If the funding comes through the station will probably be build in 2012.
  
 eVLBI will require approximately 4 Gb/s bandwidth. That will not leave sufficient bandwidth for two international stations to share the same 10 Gb/s fibre to Groningen. Changing the number of beamlets on the fly will not reduce bandwidth: it merely pads the unused channels with zeroes. eVLBI will require approximately 4 Gb/s bandwidth. That will not leave sufficient bandwidth for two international stations to share the same 10 Gb/s fibre to Groningen. Changing the number of beamlets on the fly will not reduce bandwidth: it merely pads the unused channels with zeroes.
Line 80: Line 80:
   * procedure(s) to locally check the proper functioning of the system   * procedure(s) to locally check the proper functioning of the system
  
 +=== ILT mode and stand alone mode ===
  
 +Division of time (according to ILT contract): 10% is avialable for maintenance, 90% for observations.
 +
 +10% of this 90% is available for stand alone mode, making this 9% of the total time.
 +
 +After a stand alone observation, an authorised person must do the hand over to ILT mode.
 +
 +=== International station conference calls ===
 +
 +A monthly conference call will be held around the 15th of the month to discuss technical, operational and organisational issues.
 +
 +==== Technical issues ====
 +
 +=== Station Inspection ===
 +
 +  * The Effelsberg station is visually inspected every day by security personnel, weekly by the Effelsberg operator.
 +
 +  * The Garching/Unterweilenbach station is checked every two weeks. (Station is remote.)
 +
 +  * The Potsdam station is inspected regularly, but there is no schedule for inspections.
 +
 +  * The Chilbolton station is checked nowadays about every two weeks.
 +
 +  * The Jülich station is inspected every other week.
 +
 +  * The Tautenberg station is next to the observatory and therefore checked often. A close inspection is done on average every two months, but there is no schedule.
 +
 +A remotely controlled pilot transmitter is under construction which will allow for remote testing of the HBAs of the international stations.
 +
 +=== Climatic Effects ===
 +
 +At Tautenburg, the LBAs during the winter at some time were leaning over. This was caused by snow and ice buildup on the antenna strings and rubber bands. No permanent effect.
 +
 +At Effelsberg, several LBA poles are bent. This is probably caused by heat. This effect has not (yet) been seen on other stations.
 +
 +Note that during high wind and low temperature the resilience of the rubber bands which hold down the covers of the HBA is negatively influenced, which may cause the covers to come loose.
 +
 +=== Station Maintenance ===
 +
 +Container maintenance: the firm COMTEST (http://www.comtestnl.com/index.shtml) has prepared a maintenance contract for the containers. This contract will be distributed to the persons responsible for station operations at the international stations. Note that it is the responsibility of the local station operation organisation to manage this contract.
 +
 +=== Software/firmware maintenance ===
 +
 +Software upgrades usually change the user interface, even if it is only a command-line tool. When is software upgrade is to be installed, the known changes should be summarised in a release note, which in turn is to be send to all stations. These release notes should be send well in advance to allow for comments and preparation of possible local software.
 +
 +=== Spare Parts ===
 +
 +The Effelsberg station uses first generation RCUs (the other stations use second generation RCUs). Mixing old and new RCUs is undesirable. ASTRON still has sufficient (~10) first generation RCUs to be able to support the Effelsberg station.
 +
 +=== Power consumption ===
 +
 +On average, the energy bill for a typical international station is between 5 and 7 KEURO. It is suggested that this power consumption is reduced when the station is not into use. This can be achieved by
 +  * switching to sw level 0: switches the antenna's off, but does not affect the clock
 +  * put RSP and TBB boards in low power mode. It is not known if this affects the lifetime of the RSP and TBB boards. There are temperature sensors on all TBB and RSP boards, but these are not monitored
 +  * switch off subracks: the drawback is that the subracks need to reach temperature stability again after switch on, which takes a few hours
 +Note that the air-conditioning units of the containers can only cool, not heat.
 +
 +=== Network issues ===
 +
 +There is only portal access when the station is in ILT mode.
 +
 +When in stand alone mode, LCU control can be kept intact, but LCU access should be discouraged, or even prevented in this mode. Related to this is a means to monitor the station mode (stand alone or ILT). The state should be available somewhere on the LOFAR Wiki.
 +
 +==== Security ====
 +
 +Please notify Teun Grit at ASTRON (lofar-network@astron.nl) when suspicious events happen on a LOFAR station.
 +
 +The backdoor access facility that was available until now will gradually be removed through the use of an access list.
 +
 +=== Miscellaneous ===
 +
 +Torque wrenches for the F-connectors: see http://www.lofar.org/operations/doku.php?id=maintenance:maintenance#lofar_usage_of_torque_wrenches
 ^ Action Items ^^^^ ^ Action Items ^^^^
 ^Nr ^Description                             ^Due date^Action holder^ ^Nr ^Description                             ^Due date^Action holder^
-| 1 | Determine eVLBI bandwidth requirements | soon   | Harm Munk   | +| 1 | Determine eVLBI bandwidth requirements | May 2011   | Harm Munk   | 
-| 2 | Develop application for monitoring station container conditions (T, humidity) | soon | Menno Norden | +| 2 | Develop application for monitoring station container conditions (T, humidity) | June 2011 | Menno Norden | 
-| 3 | Arrange visit to repair broken HBA tiles on DE 602 | soon | ASTRON |  +| 3 | Arrange visit to repair broken HBA tiles on DE 602 | summer 2011 | ASTRON |  
-| 4 | Update table at http://www.lofar.org/wiki/doku.php?id=operator:ilt_to_contacts | soon | all |+| 4 | Update table at http://www.lofar.org/wiki/doku.php?id=operator:ilt_to_contacts | May 2011 | all | 
 +| 5 | Check diameter of LBA poles at Effelsberg (32 or 40 mm diameter?) | May 2011 | James Anderson | 
 +| 6 | Check percentage of time available for stand alone mode | Done | Harm Munk | 
 +| 7 | Put HBA and LBA maintenance documents on the Wiki | June | ASTRON |
  
  • Last modified: 2011-05-14 07:06
  • by Harm Munk