Date: April 09, 2020

Time: 11 am Mountain, 1pm Eastern
Phone: 434-817-6468 ext 228111#
Room 220, Socorro (but Socorro people should call-in too)


NRAO: Jim, Justin
USNO: Chris, Bruce

VLBA Observations
    • Daily Observation Report (N-series)
      • PT began experiencing S-band RFI in January. RFI mitigation work was done on February 26th, achieving a 5-15 dB reduction. Most observations still seeing some RFI.
        • N20090 on March 30 was reported as "probably failed" by post-observing analysis software as was followup attempt N20090B, possibly due to RFI? USNO did report that N20090 fringed which rules out the other common failure mode of an RDBE setup problem.
    • Other Intensive Observations
      • W-series observations underway, last scheduled one is March 16th.
        • Due to recent PT-MK issues will want to extend/redo some sessions, maybe a month's worth. Discussions with WZ about when these could be done.
        • Will NOT be extended.
      • "Holiday" intensive observations at MK
        • Will be substituting MK for Kokee on federal holidays in 2020 such as 5/25/20.
        • Project code for these observations will be IYYDOY.
      • A MK-WZ observations ran on Saturdays beginning December 7, 2019 through Feb 22, 2020.
        • Project code for this observation will be QYYDOY.
        • Involves a new post-observing procedure for operators to copy the data to correlator in Japan.
        • Might restart towards end of calendar year (possibly - awaiting approval.)
      • O-series test of HN-OV baseline continues
        • Will run simultaneous with the N-series observations but will not interrupt other observing.
        • Some access problems due to loss of web portal, considering if they should go public like the other series'. Answer to that is "no".
        • Possibly expand to include another baseline like SC-BR or SC-LA (avoiding S-band RFI at BR.)
        • Possible oscillation/tracking issue at HN recently detected, suspect an elevation encoder issue.
          • Only seen at low temperatures, hasn't been noticed since January.
    • Post-Monthly Report Review:
      • No backlog from February that needed to be caught up in March.
      • Sowders replacement observation only used 3.96 hours out of requested 8 hours in March.
      • UF002CD was run at the end of March but I believe UF002CC in early March was that observation's epoch for March? But UF002C was running one epoch behind the UF002A and B series' so maybe this was it getting caught up? In any event, the request only called for three UF002s in March but four were run.
    • Pre-monthly request
      • May request adds a new 24-hour S/X series and a new intensive test series on the HN-MK baseline every other day.
      • Also asks that all of the 24-hour S/X observations no longer be made publicly available. The comment is on the new series and the UG002 series. Does it apply to the RDV as well? Probably not.
  • Open issues
    • USNO emails to ut1 list are not being forwarded along to other USNO people.
      • Not an issue with the mailing list itself, something a couple levels up from USNO in the navy.mil network.
      • Mail is being blocked at the Dept. of Defense level, working with them on that.
      • Some things were tried in late March. Results?
      • New email addresses for all USNO people? Or just some? Will be all. Not fixing the issue.
    • HN-OV baseline is more precise than any of the others USNO has data for, not sure why. Plus with all the recent problems showing up at PT maybe when fiber available to HN switch the N-series to them and PT-MK to the O-series?
      • HN fiber probably won't be in place until June or July.
      • Adding BR to the F-series for testing of additional baselines. S-band RFI might be a problem though, similar to what PT was recently experiencing but worse. Mitigation work on BR's S-band RFI probably won't happen any time soon given current situation.
        • Two of the F-series runs with BR have been correlated. Any analysis of data yet? Not yet. But it looked like only one S-band channel had to be dropped so the RFI may not be that bad with the F-series setups (which are different from the N-series setups).
    • USNO needs to renew support contract for MK fiber.
      • First invoice approved recently.
    • Networking Support Contract: Contract will be renewed for FY2020.
      • Working on renewal, might involving changing some dates on it to avoid bunching all USNO contracts up at the same time of year. VLBA might all be bundled together at a different date.
    • Correlator Refresh Contract
      • Lustre filesystem and second set of nodes still awaiting installation.
      • The new BeeGFS file system still needs to be configured and tested in Socorro.
      • The second set of nodes cannot be installed until USNO is off of their old correlator first, waiting for confirmation from USNO that they have done so. Have started parallel testing of old and new correlator.
      • Install likely on hold due to COVID-19 work and travel restrictions, though a remote installation was mentioned last month as a possibility.
      • A follow-on to the support contract is being worked on. Walter will coordinate with USNO for NRAO's side.
    • USNO is moving to new ingest data server and IP address is not working even though it's on NRAO's whitelist. USNO reports attempts to transfer data to the .179 address does not work. Looks like problem might be firewalls at USNO end.
      • Started approval process to fix problem (new firewall).
    • Transition to Mark6 recording system is done, including 4 Gbps capability.
      • Tests for transitioning to the higher data rate, perhaps with C-band, will be considered. (Though C-band has ionosphere problems.)
        • Mark Claussen will provide some 4 Gbps setups for USNO to look at for the tests. Hasn't happened yet.
      • Might be some USNO funding for more Mark6 disk drives/packs. NRAO doesn't currently have a need for more disk packs but that could change in the future once more 4Gbps observing starts. USNO has around 70 Mark6 disk packs not being used, they're small though (16 TB). Could be used for RDV data copying at Haystack or small global runs.
    • New IVS session code naming structure (long-term issue)
      • There is likely to be a change to format of the IVS "session code", but maybe not until 2021. As the USNO works to make the VLBA intensives look like IVS sessions we want to discuss what impacts such a change might have on this effort. This particularly relates to the 'exper_name' in the .vex files.
      • Intensives are all now using the xYYDOY naming format (ie, N20001, O20001, etc)
      • New IVS codes will be similar to existing codes but perhaps slightly longer, for example "NYYYYDOYNN". USNO & Goddard have discussion about it, length will be more than six characters. NRAO has already used some seven character length codes (such as "N20014B") without it causing any problems.
    • VLBA able to participate in CONT2020 (Nov-Dec 2020). Won't be a full 15-day session, maybe a "mini-CONT" of around five days. (Long-term issue)
    • Peculiar delays - VLBA has a delay compared to Kokee that perhaps should be checked out. Maybe put some VLBA stations into a KK observation as tagalongs so comparisons can be made. Walter reached out to some people, says it looks like it would be a bigger effort than anticipated and may have to wait until things return to normal.
  • Next regular telecon meeting on May 14.
-- JimOgle - 2020-04-06
Topic revision: r3 - 2020-04-09, JimOgle
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