Intro  (top)

• Their system setup:
• the feed is dual pol
• each pol has two outputs that  each go to a cooled (70k) amplifier and then a hybrid combiner.
• the output of the combiner that goes to a power splitter. 1 signal continues to their system, the 2nd output goes to the AO if/lo
• The ttl cal pulse from downstairs is fed the 1pps tick. this goes through the cbh cal pulse  line to their system for the start tick.
  
• ao signal
• there is a filter for each polarization
• polA 120 Mhz centered at 1420
• polB  250 Mhz centered at 1325

• the signal then goes to amp, pad, amp and then to the cband high cable input in the blue rack
• We used cbh  (or sbh?) cables and plugged then into lbn port 6 (should have left them into cbh.. would have saved some time).
• For pointing we used rcvNum 6 called test. the pointing model was modelTEST.
  

• The experiment number was S2841
• ended up using 162.1 for turret position
  
• Info can be found under:
• /share/obs4/usr/s2841 . the ephemerides used
• x101/140513-16
  
• During the run there was problem with one pol. The there was a bad connection where the two log periodics of 1 pol exited at the bottom of the feed.

Timeline: (top)

• 12may14: start installation of feed
• 13may14:
• finish installation of feed.
• use az,za offset and scope to find rough estimate of pointing offsets.
• calib scans. before changes do pointing model
  
•  B0518+165 with fwhm beam =12amin..2 patterns
• file=corfile.13may14.x102.1
•  B0518+165 with fwhm beam=4 amin. 5 patterns
• file=corfile.13may14.x102.2
• az strips through source at various turret offsets.
• B0758+143 (2.6Jy) 3 cycles of 9 strips
• file:corfile.13may14.x101.1
  
• B1005+077 (6.8Jy) 11 strips
• file:corfile.13may14.x101.2
• Showed that polB src deflection was 1/2 of polA when measured in Tsys units.
• 14may14:
• x102 calibration run midnite to 7:30 am
• src:B1607+268,B1843+098,B2120+168
• file: corfile.14may14.x102.1
• used this to compute the pointing model offsets. only used PolA, since polB was flakey.
• za offset: -5.53, az offset: -4.12. subtracted from modelTEST pnt model file around 9:00 am.
• tried repairing polB by soldering bad feed connection. around 9am
  
• removed feed, soldered, then reinstalled.
• did calib run. PolB is not twice as large as polA source.
• didn't fix the problem
• Looks like they reversed the cables when plugging them back into the feed.
• 13:00. calibration run on B1034+329 
• 3 patterns,. showed that they had reversed the pol Cables when reinstalling the feed.
• file: corfile.14may14.x102.2
• 13:50: az swing  270 to 630 and back za=18.
• file=corfile.14may14.x101.1
• 15:09: started tracking gps satellite
• adjusting power levels, putting in pads
  
• file: corfile.14may14.x101.2 scans 492,493
• track offset postions on gps satellite
  
• az,za Offset=.03333 Deg= 2 Arcminutes(great circle)
• 15:25:18 +az offset
• 15:26:18 -az offset
• 15:27:44 + za  offset
• 15:28:30 -za offset
• 15:29:33  back on source
• 15:31:28   1.333 deg off source in az direction (great circle)
• file: corfile.14may14.x101.2 scan 494.
• moved to 2nd gps satellite, calib 3 calib scans
• file corfile.14may14.x101.2 scans 413400495 to 413400512
• track their satellite (illuminated by radars)
• file: corfile14may14.x101.2
  
• scan 413400513 for 286 secs. then stopped to update corfile config (256-> 1024 channels, lagc 10->9) t
• scan 413400513 till end
• we tracked the sat through these cor config changes. 

• 15may14:
• tried repairing the bad pol of the feed before afternoon run
• used sky, absorber to see if the fix worked: Morning
  
• file corfile.15may14.x101.1
• scan 387. on sky  (39613 SecMidnite ast)
  
• scan 388  on absorber (39803 secMidnite ast)
  
• scan 389  on sky (40056 secMidnite ast)
  
• scan 390 on absorber (40202 secMidnite ast)
• calib scan on B0518+165 (4 patterns)
• Tracked their satellite till end of period
• file: corfile.15may14.x101.3

• 16may14:
• brought feed down to lab. tried to resolder the bad pol connections.
• reinstalled feed. polA still bad
• calib scans using different beam widths
• file corfile.16may14.x101.1
• 1405 3.7Amin  they cycled dewar during this pattern. scan: 245
• 1405 3.7 amin scan 251
• 1227 4.5 amin scan 257
• 1010 5.3 amin scan263
• 420  13.0 amin  scan 270
• They tracked their satellite for the rest of the day.
• anritus spectrum analyzer installed in dome on polB
• rfi sweep while taking data:
  
• .cover 300 to 2000 Mhz
• start: linclab_rfiswp1_000.dat 15:20 ast
  
• end: linclab_rfiswp1_196.dat  16:14 ast
• cover 300 to 3100 Mhz
• start:linclab_rfiswp2_000.dat 16:15 ast
• end:linclab_rfiswp2_364.dat  17:55 ast
  

13may14 One pol is 1/2 the strength of the other. (top)

     Azimuth strips were done through a source at different turret position (to see what the sidelobes looked like)

• there were 9 strips done in a cycle. each strip differed from the previous by (.5,.8) turret degrees (45 asecs on sky per turret deg).
• 262.1 turret degrees was used as the center.
  
• B0758+143 (2.6Jy). .5 deg turret step between strips. 3 complete cycles done
  
• B1005+077 (6.8 Jy). .8 deg turret step between strips. 1 cycle  plus 2 strips were done.

• Page 1: Src:B0758+143 (2.6 Jy)
• 3 cycles of 9 strips each were done
• The step size was .5 deg (turret). -2.0 to +2 turret degs
• black is polA, red is polB
• Each strips was normalized to +/- 12 points from the strip edge.
  
• Top: PolA and polB power vs time for the 27 strips
• all the strips were plotted in sequence

• bottom: overplot the 27 strips
• the peak moves as the turret center used steps from -2. to +2 turret degrees

• PolB is 1/2 of polA deflection

• Page 2: src B1005+077 (6.8 Jy)
• this used .8 deg turret steps (-3.2 to 3.2 turret degrees
  
• 1 cycle (9 strips) plus the first two of the 2nd cycle were completed

Summary:

• The signal to noise for polB is 1/2 of the signal to noise for PolA
• This could be because Tsys of polB is twice that of polA, or that polB input is less sensitive.

• The sidelobes look more symmetric at an offset of -2 or -1.5 turret degrees
• Looking at other calibration runs, the sidelobes sometimes looked symmetric when we were using 162.1 deg. The sidelobe may also be a function of the az,za..
  

14may14 x102 calibration run  (top)

    An x102 calibration run was done 13may14 in the afternoon and then again 14may14 in the early morning.
There is no cal for the linclab feed so the Tsys,gain measurements are not valid.  Polarization B was misbehaving so only polA was used in the reduction.
The feed was worked on after the 13may14 run, so only the 14may14 early morning data  is shown.

The plots show the calibration results on the 3 sources (.pdf) (.pdf)

• Data was taken at 1405 Mhz. 14may14 00:00 to 7:30 am.
  
• Page 1: Gain,Tsys,SEFD, Beam width
• Only SEFD and Beam width are valid (no cal for the tsys,gain)
• The SEFD is 13 to 15 Jy. (lband wide sefd is 2.5 to 3Jy)
• The fwhm beamwidth is 198 Asecs. lband wide fwhm at 1415 is 205 asecs
• the feed probably over illuminates the tertiary, giving a narrow beamwidth
  
• page 2: Coma,Sidelobe, efficiencies
• Only the sidelobe height is valid. It is about 15 db below the peak. this is similar to lbw.
  
• page 2:Pointing error:
• za offset: -5,  rms:4.1 asecs
  
• az offset: -4.8, rms 5.9 asecs
• +5, +4.78 asecs was added to the test model at 9:00 am 14may14

16may14 rfi measurements (top)

    The anritsu spectrum analyzer was connected to polB of the lincolnLab feed. It was used to monitor the rfi from 300 to 3000 Mhz.
The setup for the spectrum analyzer was:

• 300Khz RBW, 165Mhz span, 551 channels. Average 30 sweeps in trace 1, peak Hold in trace 2.
• It took about 15 seconds to acquire and record each 30 sweep specrtra.
  
• Two sets of data were taken:
• 300 Mhz to 2000 Mhz. This took 10 steps to cover
• The telescope motion was:
• tracking quasar 3c138 for a few minutes
• move  to az=370,65. so the guys could exit the dome
• Them move to start tracking the sat at for 16may14
  
• filenames:linclab_rfiswp1_000.dat -> 196.dat
  
• 300 Mhz to 3100 Mhz. This took 17 steps to cover.
• This was tracking the satellite the entire time.
• filenames:linclab_rfiswp2_000.dat -> 220dat
• 17:45 ast started moving to az=285,za=6.5
  

• ieee floating point data. little endian
• each 15 second acquisition was in a separate file
• the file contained:
• float dat[551,3]
• dat[*,0] is the frequency
• dat[*,1] is trace 1 (the average)
• dat[*,2] is trace 2 (the peak hold)
  

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