VEGAS Team Meeting

May 21, 2012



  • Dan Wertheimer
  • Mark Wagner
  • Jayanth Chennamangalam
  • Hon
  • Glenn Jones


  • Jason Ray
  • Marty Bloss
  • Anish Roshi
  • Ray Creager
  • John Ford
  • Galen Watts

Meeting Notes:

Next Teleconference: June 04. 2012

Observation Status:

Spring observations are now in data analysis phase

VEGAS Mode Development Status:

The Roach2 Design os completed and has been compiled but it has not yet been tested. Now that the team is assembled in California, they have begun work in earnest on mode 13

Testing Status:

Results of initial gain slope work on IF modules.
  • Module s/n 11 has a 4dB slope and without the compensation in place the slope increases to 15 dB.
  • With a lowered gain the slope decreased to 1 dB, but the ripple across the band increased from 2dB to 4dB. Galen will continue work and see if a positive slope can be achieved. The ripple can be in that 4dB range, but stability is a key factor. Lowering the ADC attenuator settings will compensate for the reduced gain in the IF module.

There was a problem of instability with test 4 banks in the last test run that has since been corrected. The next test will be Wednesday during maintenance.

Other items:

The GB team is close to a specification for the computers. A test GPU is coming; it can be used to do benchmark testing by GB and UCB teams while installed in GB
  • The current HPC design consists of four 4 threads, so a six core single socket will work for VEGAS
  • John will obtain a quote addressed to UC-Berkeley for one computer and Dan will place the order from the grant M&S funds.

Linux Red Hat v6 testing of VEGAS will be necessary as NRAO-wide conversion will be required in late summer/fall.
  • Plan on doing it in time for fall Galactic Center observations.
  • Once testing above is complete, staff will upgrade to RH-6 and test GB systems. Then UCB can test.

MartyBloss - 2012-05-21
Topic revision: r5 - 2012-05-22, MartyBloss
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