# Monitoring alfa stability

The stability of the alfa receiver is monitored by comparing TsysA/TsysB for each 1 second data sample. The assumption is that if a jump occurs, the two pols  will jump differently. Taking the pol ratio removes continuum sources (at least the unpolarized part). The processing is done at the end of each month. Plots are then made and entered in the monthly table (see below).

#### How the data is processed:  (top)

To monitor these jumps the following processing is done:
• Use the a2010 drift scan data. It has 600 1 second samples per drift (followed by a cal). There have been 300 to 500 drifts/month.
• For each strip compute Tsys over the 100 Mhz band for each 1 second sample using the cal. Do  this for each pol and beam (more info on how tsys is computed).
• Compute the ratio of TsysPolA/TsysPolB. This removes unpolarized continuum sources. What's left will be any gain drifts caused by temperature or jumps.
• Normalize each strip of ratios to their median value and then look for any outliers (say 2 to 4% of Tsys).
• For the strips that have outliers, plot out the original tsys data to see if it is polA or polB that is jumping.
• Using the ratio of TsysPolA/TsysPolB compute the rms/Median for each strip. Plot these versus stripnumber and day of month.

#### Description of the plots:  (top)

The columns in the plot table contain:
1. date
2. Ratio A/B img:
• Data: For each strip of the month compute TsysA/TsysB at the 1 second samples (this removes the continuum sources).
• Horizontal axis:  600 samples/strip for each of the 7 beams.
• Vertical axis: are the strips of the month.
• Notes:
• vertical dashed lines are drawn between each beam.
• You can see all the beams at once and the continuum sources are gone. You can't tell if the problem is polA or polB (see next image).
3. Beam 0,1 TsysA,B:
• Data: Tsys by strip for beam 0 (top image) and beam 1 (bottom image).
• horizontal axis: 600 points of polA followed by 600 points from polB
• Vertical axis: strips of the month.
• Notes:
• Vertical dashed line drawn between polA and polB (at sample 600).
• The ratio image shows which beam is bad. Use the TsysA/B images to see if it was polA or polB.
• You occasionally see dots across a strip spaced by about 12 samples. This is when the radar compressed the data and it took a long time to recover.
4. Beam 2,3 TsysA,B:
• Same as beam0,1
5. Beam 4,5 TsysA,B:
• Same as beam0,1
6. Beam 6 TsysA,B:
• Same as beam0,1
• Page 1: The strips with large TsysA/TsysB ratios are plotted versus sample in strip. The threshold (see col 10) is typically 2 to 4% of Tsys.
• Data: TsysA/TsysB. Each strips had been normalized to its median value.
• horizontal axis: 600 samples per strip times the 7 beams.
• Vertical axis: the bad strips in the month. An offset is included for plotting. The vertical scale is Tsys.
• Notes: vertical lines are drawn between beam boundaries.
• Page 2: For each strip the ratio TsysA/TsysB is computed and then the rms/median of these 600 points are computed. When there are jumps within a strip the Ratio rms will be larger.
• top plot: data: rms/mean of tsys ratio. horizontal scale: strips in the month. Vertical scale the rms/median. Each beam in plotted in a different color (with an offset for display).
• bottom plot: The rms/mean for the Tsys ratio is plotted versus day of month. Each beam in plotted in a different color (with an offset for display). This plot shows which days had the jumps.
8. total Strips: Total strips a2010 took for this month
9. bad strips: The number of strips who have at least one point with abs(TsysA/TsysB-1) greater than the bad threshold (typically 2-4% of Tsys).
10. bad days: this lists some of the days with the largest jumps. It does not include all days with jumps, just the bad ones.

#### The plots by month:  (top)

Each row in the table holds the stability plots for 1 month.

 date RatioA/B img TP A,B Beam0_1  img TP A,B Beam2_3 img TP A,B Beam4_5 img TP A,B Beam6 img Strips: BadRatios rms A/B total strips bad strips bad thresh Bad days: oct12 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 396 7 .03 sep12 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 511 11 .03 nov11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 211 14 .03 6b bad oct11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 259 20 .03 beam4a,6b bad sep11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 543 6 .03 beam4a bad mar11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 525 13 .03 feb11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 764 17 .03 bm 6 ratio set to constant since 6b bad jan11 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 216 7 .03 bm 6 ratio set to constant since 6b bad nov10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 124 40 .03 oct10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 151 80 .03 sep10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 779 31 .03 aug10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 353 25 .03 may10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 195 7 .03 apr10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 1139 350 .03 mar10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 741 52 .03 jan10 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 94 4 .03 dec09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 57 29 .03 nov09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 524 129 .03 alfa installed with leds. 1st part of month trouble adjusting biases. sep09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 396 90 .03 aug09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 372 6 .03 apr09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 639 172 .03 mar09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 466 188 .03 beam 5b drifting/jumping. feb09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 571 131 .03 beam 5b drifting. beam4b looks a little marginal. jan09 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 559 118 .03 nov08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 139 32 .03 oct08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 688 165 .03 sep08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 340 73 .03 beam6b died on 16aug08 aug08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 434 129 .03 beam6b died on 16aug08 may08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 388 76 .03 apr08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 434 113 .03 beam0b went bad toward the end of the month. beam 1 a and b seems to jump around more than the other beams. there was no faa radar after 20apr08 mar08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 1420 25 .03 feb08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 67 2 .03 jan08 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 41 1 .03 apr07 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 168 1 .03 mar07 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 726 79 .03 feb07 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 721 232 .03 wapp4 brd1 polB had a bad cable (dig to Filters). This caused beam6b to jump around. Fixed 07mar07. beam1b was bad during part of this month. jan07 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 155 59 .03 dec06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 398 26 .03 nov06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 498 53 .03 beam1b amp bad 9nov-21nov oct06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 452 35 .03 sep06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)(.pdf) 578 125 .03 beam5b:3,9,12,13sep beam6b:6sep aug06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)(.pdf) 467 27 .03 beam5b:17aug beam6b:13,18aug jun06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)(.pdf) 526 8 .03 may06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)(.pdf) 200 41 .03 22,23 may. lots of radar saturation. apr06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps) (.pdf) 754 80 .03 mainly 12 second radars all beams mar06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps) (.pdf) 1349 101 .03 mainly 12 second radars most beams feb06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 444 10 .03 jan06 RatioA/B bm(0-1) bm(2-3) bm(4-5) bm(6) (.ps)  (.pdf) 360 8 .03

processing: usr/a2010/mondata/a2010_stablity.pro

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