Date: March 12, 2020

Time: 11 am Mountain, 1pm Eastern
Phone: 434-817-6468 ext 228111#
Room 220, Socorro

Attending: Jim, Justin, Walter
USNO: John, Phil, Matt, Stewart, Alan, Dave, Chris, Bruce

VLBA Observations
    • Daily Observation Report (N-series)
      • PT began experiencing what we believe to be S-band RFI on January 13 or 14, first seen by operations in the post-observing check of N20014. USNO correlation confirmed lots of H-code problems in S-band. RFI mitigation work was done on February 26th, achieving a 5-15 dB reduction. The post-observing check improved from saying that the observation probably failed to saying that it probably succeeded. Some observations the check has not reported any problems at all. USNO did confirm improvement in S-band.
        • NRAO's RFI person, Dan Mertely, wondered if USNO would be able to frequency shift their observations to further mitigate the S-band RFI. - can't really do that with PFB setup. Walter suggested flagging out the affected data at the correlator. Will have Mertely contact USNO with more information on the mitigation work.
      • MK two of the X-band channels have low amplitudes and need to be removed from correlation in the W-series. Problem then also appeared at PT and then was seen at other VLBA stations in some non-USNO SX observations. A software bug was causing problems with settings for the SX mode used by the W-series but not for other SX modes such as what is used by the N-series observations. Bug was fixed on February 27th.
      • There's another issue where N-series is having to drop one X-band channel from PT when pointing to the west. Likely RFI. Not happening recently, went away?
    • 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.
      • "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'.
        • 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.
    • Post-Monthly Report Review:
      • No backlog from January that needed to be caught up in February.
      • Sowders replacement observation used 25.41 hours instead of scheduled 8 hours in February.
      • The pre-monthly request listed a UF002CC but it was actually UF002CB.
    • Pre-monthly request
      • April request appears to have two entries for the Sowders replacement observation? One is for 16 hours at X-band but has the usual Sowders replacement observation note saying it's a maximum of eight hours and the second is for eight hours at S-band but does not have the usual Sowders replacement note.
  • 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 network.
      • Mail is being blocked at the Dept. of Defense level, working with them on that. Have not instituted any workarounds yet.
      • Some things have been tried, didn't work. Waiting on clearer instructions for some more things to try.
    • 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 might happen in the next couple of months, similar to what was done at PT.)
    • USNO needs to renew support contract for MK fiber.
      • First invoice approved recently.
    • Networking Support Contract: Contract will be renewed for FY2020.
      • Renewed or not? USNO will check into it. Working on it, might involving changing some dates on it to avoid bunching all contracts up at the same time of year.
    • 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.
      • Earliest likely install would be late April.
      • NRAO instituted travel restrictions due to COVID-19 which might delay installation. A remote assisted install might be possible.
      • 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.
    • Transition to Mark6 recording system is underway, 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.
  • Next regular telecon meeting on April 9.

-- JimOgle - 2020-03-09
Topic revision: r2 - 2020-03-12, JimOgle
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