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CICADAGreenBankSpectrometer2014Jan17
(2014-01-17,
AmandaKepley
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17 January 2014 Testing
17 January 2014 Testing
Goals
Questions to Answer
Log
Data Analysis
Goals
see how the ripples change in X-band in mode 1 or 2 with different attenuation levels
running archivist to record measured power.
Richard's suggestion was to run different levels from -20 to -15 or so to see how things change.
we have all eight banks hooked up to see if it changes between banks.
Try test with both mode 1 and mode 2
want to do a long integration on X-band at best attenuation levels to see what's up.
Questions to Answer
Is there another balance level that minimizes that ripples?
Looks like -18 to -17 might be better for mode 2 and for some cases in mode 1.
Is one polarization consistently better than another?
In mode 1 LL has worse ripples than RR. Mode 2 LL and RR are similar
Do all the banks show the same behavior?
mostly
Do some of the features correspond to known RFI at X-band?
Looks like crud at ~9.3 GHz is known RFI.
Log
Session 29
running mode 1 with archivist and with VEGAS
F and H failed to balance
problem in converter rack modules
otherwise can control the balance
Note that X-band is not at the focus position right now
Testing mode 1
Scan 7-8 -- test scan target level -18
Scan 9-10 -- test scan target level -20
Scan 11-12 -- test scan target level -19
Scan 13-14 -- test scan target level -18
Scan 15-16 -- test scan target level -17
Scan 17-18 -- test scan target level -16
Scan 19-20 -- test scan target level -15
Pause for Mike Stennes to get Ku-band installed.
Testing Mode 2
Scan 21-22 -- test scan target level -20
Scan 23-24 -- test scan target level -19
Scan 25-26 -- test scan target level -18
Scan 27-28 -- test scan target level -17
Scan 29-30 -- test scan target level -16
Scan 31-32 -- test scan target level -15
Data Analysis
Plots and analysis scripts are in /users/akepley/scratch/vegas_tests/vegas_test_17Jan2014
test.analysis describes what I did.
compare_levels.pro is a helper routine to plot the different spectra
the directories mode 1 and mode 2 have plots comparing the spectra for different modes.
the colors are red=-20, white=-19,green=-18, orange=-17, purple=-16, cyan=-15, magenta=-14.
Mode 1
The ripples are always noticeably larger in PLNUM=0 (LL) than in PLNUM=1 (RR).
Banks F and H did not balance.
For Banks A through C, I'm finding good levels at ~ -18 (+/- 1).
For Banks D, E, and G, I'm finding good levels at -20
Mode 2
-20 dB has some serious ripples. The ripples are about the same amplitude in both polarizations.
balance at -17 or -18 seems about right.
--
AmandaKepley
- 2014-01-17
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Topic revision: r1 - 2014-01-17,
AmandaKepley
CICADA
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