shimming the horn to find the focus

---

What we did:

• 16may23:
  
• receiver cool down on telescope
• 17may23:
• field fox measurements at output of filter box.
• crosses on the sun
  
• Azimuth swings at el=6..81 deg in 5 deg steps.
  
• 18may23:
• measure power coupler before FoTx: abs, sky, sun
• used fb command so filter bank setup ok.
  
• 20-21may23:
• xband crosses on crab,m87,cygA,casA)
• -->ifsetup had bug, filter bank not being setup.. probably straight thru moce
  
• 25may23:
• insert 15db pad in filter location for straight thru mode
• measure power at coupler before FoTx. measure on  sky, sun
• -> setup ok since used fb command directly.
• step cal 2700 to 12ghz no 12db  pad, but ifsetup bug do filterbank not updating.
  
• put 12db pad after coupler, before FoTx
• --> fixed bug ifsetup.. fb command had been commented out filter bank not configured correctly
  
• measure power levels at FoRcv  (before udc input)
• step cal 2700 to 12ghz with 12db pad in
  
• 26may23:
• crosses xb. with 12db pad in front of foTx. m87,casA,crab,cyg
• 29may23:
• remove  12db pad from in front of foTx
• step cal 2.7 to 12ghz with 12db pad out
  
• measure power udc input
• crosses m87 (then pwr dip). short cygA next morning
• 30may23:
• measured cal sky  & absorber
• field fox spectral measurements at foTx coupler each filter to get spectral density
• 31may23:
• morning: took out one of the 1" shims. antenna now 1" farther from the secondary.
• evening: took cross scans m87,cygA with 1" shim out
• 01jun23:
• noon removed 2nd shim. now 2" away from initial 22.6" distance horn to 2ndary
• evening: took cross scans m87,cygA with 2 1" shims out
• sky 02jun23 6:48 am (.jpeg) 
• 02jun23:
• continued crosse till around 9:00
• 14:00 put 2 shims back in
• installed cal values from 30may23 for xbfilter freq range. recomputed crosses 29,31,01
  
• start crosses around 15:00
• 03jun23
• xb crosses crab,m87,cyg,casA.. till 15:00 04jun23
• 04jun23:
• wb3: 3ghz crosses m87,cyg,cas
• 06jun23:
• wb3 (3ghz) az swings 6 to 80 deg el look for direction of 5g rfi. (more info)
  
• 07jun23:
• installed 3 inch spacers
• wb6 crosses on m87,cyga,casa
• 08jun23:
• 3" spacers still installed
• wb3 crosses on m87, cygA
• 09jun23:
• 4" spacers installed
• wb3 crosses on m87, cygA,casa
• 10jun23:
• 4" spacers installed
• wb6 crosses on m87, cygA,casa
• 11jun23:
• 4" spacers installed
• wb6 crosses on m87, cygA,casa
• 12jun23:
  
• still 4" spacers
• wb6 crosses m87,cyga,casa
• 13jun23:
• still 4" spacers
• wb3 crosses m867,cyga,casa
• 14jun23: 5" spacers
• wb6 crosses on m87,cyga,casa
• 15jun23: 5" spacers
• wb3 crosses on m87 cygA,casA
• wb3 20 minutes on B0329+54 pulsar
• 16jun23:5" spacers
• wb3: recombination lines grp1 (ssrecomb)
  
• wb6 crosses cygA,casA
• file prefix is ssrecomb...
  
• 17jun23: 5" spacers
• wb3: M42A recomb lines. (a4002) (rain)
  
• wb6 crosses m87,cygA,casA..
• rain during m87
• 18jun23:
• wb3: W3 recomb lines (a4002) (rain)
  
• wb3: psr data: B0329+54,B0833-45,B0950+08,B1133+16 (sspsr)
  
• wb3: sgrA  on's  (a4002)
• 19jun23: went back to 4" shims.
• wb6: xb crosses cygA .. cloudy at start.
• 20jun23
• remeasure cals with 4" shims
• xb: radec map of casA .. to test mapping +/- 1deg (x101)
  
• wb3: mbm sources (a4002)
• xb: map cygnusA  regular cal (x101) +/- 1deg
• files: x101.20230621.xxx   filenums: 0 - 12400
  
• pattern_id:317200001
  
• 21jun23
• wb6: radec map cygA using regular cal and  then with winking cal (x101)
  
• regular cal: x101.20230622.xxxx
• filenums: 0..12400
• pattern_id:317300001
  
• winkingc cal: x101.20230622
• filenums 12500-14900
• pattern_id:317300126
• 23jun23:
• wb3: crosses on 3C123.
  
• 26jun23:
• wb3: ips test
  
• 27jun23:
• wb3: crosses on 3C84
• first set pshift=0, 2nd set pshift=1 to stop butterfly overflows.
  

---

16may23:Receiver cool down on telescope

    Felix started the cool down around 16:00 on 16may23:

    The plots show the dewar temp, vacuum pressure and drain current during the cooldown (.ps) (.pdf)

• The blue vertical lines mark the start,end of cooldown
• It took about 4.6 hours for the 16K stage to get to 12.4K
  
• Page 1: full scale plots
  
• top: dewar temp vs time.
• black 70K stage
• red : 16K stage.
• Middle: vacuum pressure.
• You can see jumps at 270K and 70 K where water and nitrogen freeze out.
• bottom: drain current
• black in polX, red is polY
• Page 2: blowup toward end of cool down
• I flagged 12.4K as the end of the cooldown. it actually went a few tenths of a kelvin lower.

processing: x101/230516/cooldown.pro

---

17may23: Field fox measurements at filter box output.

• Crosses on sun
• field fox setup: 10001 pnts,2-12 ghz,attn=0db,rbw=1Mhz,avgdetect
• had a 12foot cable from filter box output to field fox input. 7.3 db loss.
  
• suncr_az_az/el  10 am, 11 10' steps. didn't get off sun for high freq
• preamp off
• suncra_az/el 10 am. 22 10' steps +/= 1.8333 deg
• preamp off
• suncrb_az/el: 10am, 22 10' steps, +/- 1.8333 deg
• preamp on
• Programs:
• datataking: /share/obs4/usr/p12m/wbrcv/comm_230517.tcl
• processing: x101/230517/
  
• Az swings:
  
• drive az .2 deg/sec -90 -> 270.
• do at el = 6 to 81 deg in 5 deg el steps.
• ff setup: preamp off,attn=0,1001pnts,  on swp,avgdetect 2-12Ghz
• 6 secs for each spectra (1 swp). gave points every .2*6=1.2 deg in azimuth
• output directory: /share/phildat/wbrcv/230517/
  
• file names azsw_00_el_nnn.az.dat
  
• el: 06,11,..81
• nnn 0.. 216,
  
• az- azimuth of points
• Program:
• datataking: /share/obs4/usr/p12m/wbrcv/azsw_230517.tcl
• process: x101/230517/xxx.pro

---

18may23

• measure power levels at Fo coupler
• straight thru mode is a cable
• no 12db pad before FoTx
• on abs, sky: az,el=(-95,5.9),on sun

---

25may23

• 15 db pad inserted in place of cable for straight thru mode of filter bank
• measured power levels at FoTx coupler for all 6 filter positions.
• on sky, sun
• put 12db pad after coupler before FoTx
• measured power levels at FoRx output (before udc input)
• cycled calon,off 2.7 -> 12Ghz with mocks