220123: 5 sec rfi seen at 12meter site

• the vertical axis is freq
• the horizontal axis is time.
  
• spectra are sampled every .25 seconds.
• The vertical  lines are the comb
  

The plot shows some properties of the comb (.ps)   (.pdf)

• Page 1: avg spectra and rmsbychan
• Top: average spectra for the 1 hour
• Black is polA, red is PolB
  
• bottom: rms/mean by chan
• Page 2:
• top total power vs time
• Data is sampled every .25 seconds
• black is polA, red is polB
• Middle: blowup total power vs time
• The purple line is the clipping level used to average the spectra with the spike
• The spikes are spaced by about 5.5 seconds
• Bottom: plot average spectra with and without the spikes.
• Black, red are the spectra with the spikes (PolA,B)
  
• Green,blue spectra without the spikes.
• There  largest different in power is around 48 to 54 Mhz.
• Page 3: magnitude of total power spectra.
• This was used to get a more accurate period.
• 3600 seconds of data was used.
• top: total power spectra 0 to 2 Hz.
• black is polA, red is PolB
• Bottom: Blowup in freq
• the  comb has a freq of .181 hz or 5.53 seconds

Summary:

• When callisto was at the 12meter site, a 5.53 second comb was seen in the data
• The comb was always there.
• period:.181 hz, period: 5.53 seconds
• when callisto was moved to the staging area, the comb disappeared.
  

processing : x101/210125/ecalrfi.pro

220126: test rfi with trailer door open,closed.

    The callisto system was moved to the staging area on 220125. The electronics was placed in and rfi tight trailer while the antenna was placed on the roof of the adjacent trailer.

    On 26jan22 we looked to see if the  callisto electronics was getting into the rf signal. The setup was:

• The antenna was placed on the ground above a ground plane (prior to moving it to the roof of the adjacent antenna).
  
• The electronics was inside the trailer.
• The field fox spectrum analyzer was in the trailer. It was fed one of the  callisto antenna polarizations.
• The  field fox settings were:
• rbw: .25 Mhz
• cfr: 45 Mhz, span 50 Mhz
• Peak hold.
• Data was taken for 30 seconds with the door open and then about 30 seconds with the door closed (the times may have been a little different).

The plots show the spectra with the door open and closed (.ps)  (.pdf)

• Top: spectra with door open and door closed
• Black door closed
• red door open
• Bottom: the ratio of DoorOpen/DoorClosed

Summary:

• the spectral density was  a little higher when the door was opened vs when it was closed
• I may have let the peak hold run a little longer on the door open.
• There are no large spikes that appear when opening the door.
• We may want to repeat this after the antenna is moved to the top of the adjacent trailer (and i will try to do a better job of making the times equal :)

processing: x101/220126/callisto_rfi_door.pro