• 26jul23:  a4002 3 GHz rfi from 1-9jul23 data
  
• 14jul23:  testing the rfi from the cameras mounted at the 12meter with the cooled reciever.
  
• 27jun23: comparing mock pfb overflows using noise and radar shifts for 3Ghz pulsar data.
  
• 27jun23: a4005 xband at 9103 sees instability in the upper portion of the band (8730 to 9100 Mhz rfi)
  
• 15jun23: 3Ghz data B0329+54 shows lots of polB rfi.
  
• 06jun23: 3ghz az swings el 6,10,20,30..80 deg
  
• 28mar23: check dewar monitor box rfi in screen room after osvaldo worked on it.
  
• 06mar23: test filterbank box in the screen room.
  
• 01mar23: summary of 8730 to 9100 Mhz rfi in xb receiver.
  
• 11jan23:  first rfi test of dewar monitor box in screen room.
  
• 28nov22: nov22 processing of 60hz data showed jump in freq when cal box removed, reinstalled.
• 18nov22: voltage sampling 2322 looking at siriusXm signal.
  
• 10nov22: more calbox tests, reverse cal cables, bias cables.
  
• 09nov22: see if the calbox was the source of the 120hz saturation in polb,
  
• 04nov22: sb, removing cal fiber causes 120hz saturation in polB
• 02nov22: test new camera on top of 12m control building.
  
• 21oct22:  sband spectra at input to postamp chassis.
• 13oct22:  problems with pulsar observing corresponds to 60 hz in polB
  
• 31aug22: testing stationary surveilance camera on 12meter control building roof.
• 30aug22: rfi seen in 30aug22 az swings.
  
• 30aug22: redo az swings at low elevation to see Tsys  improvement after brush cleared.
  
• 26aug22: testing surveillance camera at 12meter pad.
  
• 24aug22: testing surveillance camera on tower by visitor center hill
  
• 12aug22: xband az swings done at low elevation.
  
• 21jul22   cygnus xb mapping sees saturation form rfi 8732 to 8968 Mhz
• 21jun22   qrfh horn. azimuth swings covering 2 to 12 ghz showing rfi  az dependence.
  
• 2may22  xband az swing using azstep routine. 8319-8349 MHz rfi
  
• 22mar22  sband azimuth swings.
  
• 11mar22: sband spectra at input to postamp chassis (before and after new sband filter)
• 09mar22: s-parameters for new sband rf filter.
  
• 08sep21: rfi 8319 to 8349 Mhz seen when make pointing model 4A.
  
• may21 -  0-3 Ghz rfi measured at 12meter site with discone antenna and field fox spectrum analyzer.
• 22apr21 - rfi 0 to 1 Ghz at 12 meter using discone antenna.
• 20apr21 - sband spectrum at input to the post amp chassis.
  
• 25feb11 - checking rfi inside the pedestall

fcc Allocations:

• 8750-8850:airborne services: 47.87 airborne  doppler radar. 47.87. freq table 47.87.173
  
• 8500-9000 private land mobile radio services 47.90. freq table49.90.103 share but secondary to airborne doppler

Rfi details

210908:  8330 Mhz rfi

    On 8sep21  crosses were done on 3C273 with the 12meter using xband (for pointing model). The setup was:

• Az,El strips of 1.2 degrees were done (2 minute each).
• The mock spectrometer was used to record spectra:
• .1 sec integration
• 172.032 Mhz bw, 1024 channels
• Tbe band centered at 8350 Mhz showed rfi. This rfi was often seen.
  

    To process the data.

• The average specdtra was computed for each 120 strip.
• the rms/mean by freq channel was computed for az strip
• the source deflection did not skew the rms/mean much as we drove over the source.

The plots show the rfi seen 8319 to 8349 Mhz  (.ps)  (.pdf)

• Top: average spectra for each 120 second strip (105 in total)
• Black in polA, red is polB
• The purple lines flag the limits of the rfi: 8319 to 8349 MHz
• Bottom: rms/mean by freq channel for each 120 second strip.
• there are 1200 .1 second samples in each strip.
  
• The expected rms/meanis : 1/sqrt(168e3*.1) = .008. The green line shows this value.
• There are large deviations in the 8319-8349 Mhz section of the spectra.

Summary:

• rfi was seen between 8319 and 8349 Mhz
• This rfi was seen every day the model 4a data was taken.

processing: x101/210908/210908_8330rfi.pro