800 band RFI measurements.

• 03dec10: article.. 700 Mhz band plans
• article: 700 Mhz band allocation, auctions
• FCC 700 Mhz Band plan table (.pdf)
  

08mar11: alfa motor and dome cameras: rfi in 800 rcvr

• 800 Mhz rcvr centered at 750 Mhz
• mock spectrometer using 2 57 Mhz bands with 8192 channels each.
  
• low band: 730 Mhz center
• hi band: 770 Mhz center
• 300 1 second integrations.

• 730 Mhz polA (.gif)
• camera birdies at:701.5, 717,730 visible
  
• 730 Mhz polB (.gif)
• camera birdies at:716.66,730.22 visible
• motor birdies:725,757 drifting to lower frequencies
  
• 770 Mhz polA (.gif)
• motor birdies: 757,797 drifing to lower frequencies.
  
• 770 Mhz polB (.gif)
• motor birdies: 757,797 drifing to lower frequencies.

• The bandpass was removed with a harmonic fit so constant birdies will remain.
• Page 1:alfa motor off (black), motor on (red).
  
• The off spectra was shifted .05 Mhz to the left so the on,off would no lie on top of each other.
• Top polA, bottom polB.
• the motor birdie is not strong enough to see in the average (since it drifts in frequency).
• Page 2: cameras off (black), cameras on (red).
• The off spectra was shifted .05 Mhz to the left so the on,off would no lie on top of each other.
• Top is polA, bottom is polB.
• The green lines show the location of the camera birdies (they are stronger in polB).
• 740-760 looks rougher. This is the overlap region of the two bands.

• the alfa motor controller rfi is visible at 757 and 797 Mhz
• The motor birdies drift to lower frequency when they device is turned on.
  
• The dome cameras make rfi at 716.66 and 730.22 Mhz

29nov10: FCC 700 band auctions:

• Block A: 12 MHz (698-704 / 728-734 MHz) (EA licenses)
  
• Block B: 12 MHz (704-710 / 734-740 MHz) (CMA licenses)
  
• Block E: 6 MHz (722-728 MHz) (EA licenses)
  
• Block C: 22 MHz (746-757 / 776-787 MHz) (REAG licences)
  
• Block D: 10 MHz (758-763 / 788-793 MHz) (nation wide)

Notes:

• 01oct08: venturetel defaulted on it's interim payments, so it's license was revoked.
  

25aug09: azswing looking for chn 67 peak after chn turnoff.  (top)

• az spin at .38 deg/sec and za=18.
  
• mock spectrmeter sampling at 172Mhz bw, 8192 channels and .1 seconds.
  

• the plots are power in a single channel (21khz) vs azimuth
• black: 289.25 video carrier
• red: 793.75 audio carrier.
• green: baseline taken as a range of freq below the video carrier.

12aug09: tv chn 67 turns off. (top)

• Mock spectrometer with 8192 channels across 172 MHz
• .1 second averages , averaged down to 1 second.
  

• The dashed horizontal line shows when the station turned off. The following birdies went away:
• 710.75 - mixer image of 789.25
• 775.6, 780.1
• 784.71 - 3rd order intermod 2Fvideo - Faudio
• 789.25, 792.83,793.75: video,chroma, audio of chn 67
• A weak narrow birdie remains at 789.25 (video carrier). Either the station did not completely turn off, or there is another transmitter somewhere on the island.

• Black is channel 67 On,  red is channel 67 Off. I averaged about 100 seconds of spectra before and after the turn off.
• Top: PolA channel 67 on (black) and off (red). The vertical scale is db above Tsys. The video carrier is about 35 db above the noise floor.
• 2nd: PolA blowup. Same plot as frame 1 but  using a linear  scale. The horizontal and vertical scales have been blown up.
• 3rd: polB shows station on and station off using a db vertical scale.
• bottom: polB blowup using a linear scale.

• The station turn off removed all of the intermods/harmonics coming from the tv station as well as the audio and chroma carriers.
• The video carrier went from 3162*Tsys (35db) to .8*Tsys.
  
• The remaining video carrier could be coming from this site or another  transmitter somewhere in pr.

18jun09: freq hop 750 -> 753.7 MHz. source of rfi.  (top)

The setup:

• az=240, za=10 sitting.
• 172 MHz bandwidth, 8k channels, 1 second integrations, mock spectrometer.

• Top: Average spectra linear scale.
• The peaks have been clipped.
• Black is centered at 750MHz, red is centered at 753.7 MHz.
• Bottom: Average spectra db scale (above Tsys).
• the colored lines group rfi that is related.

Summary:

• When the az,za was 240/10 all rfi can be  attributed to chan 63 or chan 67  except 744.6 MHz.

14jun09: azimuth swing (top)

The setup:

• az 270 -> 630 degrees. az velocity about .38 degrees/sec.
• za=18 degrees and fixed
  
• 172 MHz band centered at 750 MHz.
• Sample data at .1 seconds.

• The vertical scale is -90 to + 270 degrees of azimuth.
• polA and polB have been averaged.
• the large triple rfis are video, color, audio carries for tv stations:
• 765.25 : chan 63
• 789.25 : chan 67
  

• Page 1: average spectra for the entire azswing:
• top: Average spectra (linear).
  
• The maximum value has been clipped.
• The colored lines show the frequencies that are plotted vs azimuth on page 2.
• bottom: Average spectra db scale.
• 765.25 chan 63 average value is 42 db above Tsys.
• Page 2: rfi channels versus azimuth.
• The black vertical lines show the peak az of channel 63.
  
• The red vertical lines show the peak az of channel 67.
  
• top: strong rfi
• 765.25: channel 63.
  
• The peak value is at az=24.4, 55.2, and maybe 0.
  
• The signal has clipped (probably in the 40 bit accumulator of pdev).
• 789.25: channel 67 . azpeaks at -54.3 and 49.
• 793.78: the audio carrier for channel 67.
• Bottom: weaker rfi
• All of the azimuth positions for these rfi frequencies line up with the chan 63 or chan 67 az peaks.
  

SUMMARY:

30oct08: Check how clean 839 Mhz is using hilltop monitoring data for oct08.  (top)

• A time series for the  power at 839  Mhz was made using the hilltop monitoring data  taken in oct08.
•  1 Mhz about 839 Mhz was used (probably the average of two spectrum analyzer channels).
  
• Data was sampled every 19 minutes.
• The plot is a db scale with an offset for display. Each color is a separate day (oct 1 is on the bottom).