TGBT15A_915_124 - Tests of Spectral Line balancing

Goals

• Run X-band Modes 1-29, check balance

Details

• Get started around 3pm - New manager, new HPC
• Use X-band
• Quick test with mode 10; IF Rack genuinely fails to balance; VEGAS reports this.
• Quick test with mode 1; Converter rack fails to balance; again, reported correctly.
• Filler was not running, restart...

• Scans 15/16: Mode 1: CM13,14,15,16 fail to balance
• Scans 17/18: Mode 2: same
• Scans 19/20: Mode 3: same
• Modes 4, 5, 6, 7, 8, 9 same
• Modes 10 - 15: IF Rack also fails to balance.
• Abort after Mode 15 to switch versions.

• Summary - LBW Gain now seems to be getting set correctly, but IF genuinely is not balancing correctly.

• Strange symptoms:
  • mode 1: Scan 15, TP plnum=0, ifnum=0, no signal from 8.2 through 8.8 GHz in either polarization. Ok in other banks
  • same in modes 2,3
  • In all higher modes, plnum=1, ifnums 4 through 7, which do not balance correctly, have large DC offsets in their spectra.

• Switch back to old manager, old HPC
• Spot check Modes 1 and 10. All look ok, so this apparently was a new VEGAS problem, possibly due to following Ryan's pulsar testing.