TGBT14A_912_62 - Testing Bank to Bank variations with noise source

17 and 21 January 2015

17 January 2015

  • We cannot use Astrid, so simply use VEGAS and the Archivist
  • Use the noise source with an eight-way splitter, and connect up both pols of banks E,F,G,H to one noise source output
  • The previous observer was using KFPA, so VEGAS will have been configured for that.
  • But, Ray releases a new version of the Manager, so it will loose knowledge of where it was.
  • Use VEGAS quick-set to set tp_nocal
  • Configure Archivist DAPs manually.
  • Set Archivist to above project, source name "KFPA", and 60 sec scan time
  • Got scan name wrong - became scan 103. Start time 15:36:37 - but went into _61 directory, so that is ok
  • Scan 1: 15:40:14
  • This all works fine; samplers are all logged into the /home/gbtdata directory.
  • Write Archivist procedure to configure and run Archivist:
[rprestag@titania noiseTests]$ source /home/gbt/gbt.csh
[rprestag@titania noiseTests]$ source /home/gbt/sparrow/sparrow.tcsh
[rprestag@titania noiseTests]$ ipython -i control.py
  • Scan 2: started through control.py
  • Ray restarts VEGAS - should come back to mode 22, since Coordinator was not restarted.
  • Scan 3: junk test of procedures
  • Scan 4: start both Archivist and Vegas; vegasdm is reporting ~ -24dB in all channels
  • Need to set lbw_gains manually, since I don't have a vegas balance option
  • Need to deselect banks A through D, and set up tp_nocal
  • Note - all subband frequencies are set differently; need to make these the same
  • Scan 5: looks like everything is working correctly.
  • Write setSubFreqs() to set all sub-band frequency values to 750000000
  • Jason changes 6dB pads to be 3dB pads. measpwr levels are now around -21dB +/- 0.4dB
  • Scan 6: Note that sbNsnap values are around -40dB, even though lbw_gain is set to 1024. Why is this?
  • VEGAS files seem to have the wrong data in them; Archivist data is fine - what is going on? Try again
  • Scan 10: still wrong. Need to set next scan number in coordinator? - Yes
  • Scan 10: works correctly now. Now want to plot the data.
  • For reasons I don't understand, the sbNsnaps are really low when lbw_gain = 1024. Looks like we need 16384. Set all subbands to this.
  • up until now, I had only been configuring banks E and F (typo in control.py script)
  • Scan 11: Should now all be set up correctly for all four banks, and correct values of lbw_gain.
  • Archivist file is: 2015_01_17_18:39:48.fits VEGAS is: 2015_01_17_18:39:44H.fits

  • So, I think I am all configured now for Mode 22. Take a scan with no attentuation, then change the attenuation
  • Scan 12. Zero input attenuation. Arch: 2015_01_17_19:23:56.fits VEGAS: 2015_01_17_19:23:53E.fits
  • Scan 13. 1dB of attenuation. Changes input power level by almost exactly 1dB. Output snap blocks still look sensible
  • Scan 12 0dB
  • Scan 13 1dB
  • Scan 14 2dB
  • Scan 15 5dB
  • Switch to Mode 21 (Dana's broken mode). Just change mode number in CLEO screen - Can't! CLEO is broken. Use Dev Explorer
  • VEGAS CLEO screen does not reflect this, but VEGASDM does. sb1snap is now -43dB. lbw_gain has gone back to 1024. Set to 16384
  • All looks good.
  • Scan 16 0dB
  • Scan 17 1dB
  • Scan 18 2dB
  • Scan 19 5dB
  • Switch to Mode 11 (A supposed good mode. Shouldn't need to change anything else, but we'll see. Seems ok.
  • Scan 20 0dB - note, sb1snap values have become asymmetric: pol1 has moved to ~ 25, and pol2 to ~ -25
  • shift is slightly different from bank to bank. Effect is not there in input samplers, and I don't recall seeing it before.
  • Scan 21 1dB - bank-to-bank changes in sb1snap ADC peak is much more pronounced.
  • Scan 22 2dB - bank-to-bank changes in sb1snap ADC peak is extremely pronounced.
  • Scan 23 5dB

  • Look at Mode 4 - can I set this up correctly? setMode() seems to have done it - hopefully Valon freqs, etc, are ok.
  • filtersnap values are again way too low, ~ 40dB. Set lbw gains to 2**30 = 1073741824. Only comes up to -30dB.
  • probably need to set some other value. But I don't know what else to set. Stop here, and concentrate on data analysis.

  • With astronomical signals going in, need lbw_gains of 1024. Must be that the noise source cuts off at the frequency of the subband I chose?

  • 6pm: Jason configures VEGAS back up as normal. play around with lbw_gains; looks normal again.

21 January 2015

  • 9:00am - Jason configures noise source again
  • Use Astrid to configure for L-band; Mode 7 - bank_gain_mode7_lband
  • Remove A,B,C,D - need A to Quickset phase table
  • switch period and integration time set to 1 secs.
  • Only one subband in use - set to 400 MHz. Leave it there
BANK  lbw_gain
   E     874577333
   F     834781943
   G     842144254
   H     848663467
  • All input powers around -20dBm, and all filtersnap values about the same.
  • scan 30 - mode 7, 0dB input attenuation; all looks correct
  • scan 31 - mode 7, 1dB
  • scan 32 - mode 7, 2dB
  • scan 33 - mode 7, 5dB - Bank E has a 10dB "dropout" to -35dB - run again
  • scan 34 - mode 7, 5dB - looks ok.

  • 2pm. return to work. Configure for mode 4 through Astrid
  • All subbands are set to 750MHz - leave them like that. Input values and balancing looks good.
  • Note: G & H pols agree perfectly; E and F differ by ~0.4dB
BANK  lbw_gain
   E     3695684124
   F     3798716948
   G     3636967430
   H     3784571147
  • Integration times below were incorrectly set to 4secs, change to 1 sec
  • scan 35 - mode 4, 0dB
  • scan 36 - mode 4, 1dB
  • 1 sec integrations
  • scan 37 - mode 4, 0dB
  • scan duration is somehow way too short - aborting due to detection of invalid data. Cycle Off/On
  • Now complaining about integration time; set blanking time to 0? can't. Did this affect other scans
  • scan 38 - mode 4, 0dB - now seems ok
  • scan 39 - mode 4, 1dB
  • scan 40 - mode 4, 2dB
  • scan 41 - mode 4, 5dB

  • Change to mode 3. run bank_gain_mode3_lband - leaves VEGAS in mode 4!! Suddenlt CLEO flipped to Mode 3 - ok?
  • In this mode, there are no output samplers, just the input sampler.
  • scan 42 - mode 3, 0dB - all seems ok
  • scan 43 - mode 3, 1dB
  • scan 44 - mode 3, 2dB
  • scan 45 - mode 3, 5dB
  • all done for today!

-- RichardPrestage - 2015-01-17
Topic revision: r8 - 2015-01-27, RichardPrestage
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