Checking rfi from site cameras
24aug22
Measurements:
24aug22: moveable
camera at tower on visitor center hill
26apr22: moveable
camera at 12meter cement pad
31aug22: stationary
camera on top of 12meter control building.
02nov22: new stationary camera on top of 12meter control
building.
14jul23: testing the
cameras installed at the 12meter with the cooled receiver.
On 14jul23 victor and i tested the
surveillance and web cameras located at the 12meter site.
The setup:
- wb3: 3Ghz filter used to take the data
- mock spectrometer took the data
- 5x172.032 bands, 8192 chan/band, 1sec integrations,
pshift=radar
- center freq: 2846 2988 3130 3272 3414 Mhz
- data output to
/share/pdatan/pdev/x101.20230714.bns1g0.00000.fits
- 2159 seconds of data taken
- file started at: 11:00:32.
- all sets are in this file
- Looking at the 2 cameras on cement pedestal west of
12meter
- az=220, el=10 deg
- cycling on, off of the cameras
- 11:00:32 pointed at cement
camera on start scan
- 11:02:10 camera off at
cement
- 11:04:04 camera on..
- 11:06:10 camera off
- 11:08:10 camera on
- 11:10:21 start moving tel to 5
50 in prep for pedestal test
- Processing the data
- 589 spectra for each of the 5 bands was used to make
dynamic spectra
- The median spectrum was used for the bandpass
correction
- the image was scaled to +/- 3sigma full scale
- The table below shows the dynamic spectra for each band
- the green lines show where the cameras were turned on
- the red lines show where the camera was turned off
-
- You can see a comb that is turning on, off with the
cameras
- Previously a 15.625 Mhz comb was seen in some of the data.
Summary:
- The camera on the cement block is making lots of rfi
- This is not the same camera setup that was measured back
on 221102.
- The previous measurements used the warm receiver (tsys up
to 180 K)
- The current receiver has a Tsys around 40 to 50 K
- We also are looking at 2.75 to 3.5 GHz
- the old receiver had a narrow band around 2250 MHz.
- The camera at the cement block and the camera above the
12m control building were both turned off around 15:30
14jul23.
- They should stay off
- I still need to look at the data
- taken with the camera above the control building
- turning the motor controller of the 12m on,off
processing: x101/230714/rficamera.pro
24aug22: moveable camera at tower on
visitor center hill.
Intro
Arecibo is installing a large number of
surveillance cameras around the site. Rfi testing was done with
the 12meter to see if they will cause unwanted interference.
Setup:
- This was the moveable camera.
- The camera enclosure (sitting on the electronics bench
.jpg)
- the camera was placed inside a transparent plastic box
with shielding on the inside of the box.
- The power over ethernet camera cable went into
through the tube down to a huffman box that contained the
ethernet switch.
- The camera was mounted on top of the tower on the
hill up to the visitor center (tower.jpg)
- The 12meter telescope was rotated to az=-150, el=6deg to
point back toward this location.
- The 12meter sband receiver was used. The center freq was
set to 2270 MHz.
- The mock spectrometer was used to record the spectra:
- 1 mock box, 172.032 MHz bw, 8192 channels, pola,b, 1
second integrations.
- the data recording was started on a 1 second tick
and ran continuously during the test.
Testing procedure:
Felix turned on and off the camera using
about a 2 minute cycle.
- To turn on the camera he had to open the huffman, turn on
the power and the close the huffman box
- After turning on the camera it would move in azimuth and
elevation for about 40seconds.
- To turn off the camera, the huffman box had to be opened
to shut off the power.
- The test cycle was:
- turn on the camera, report time
- report when moving stopped
- turn off the camera and report time
- The table below shows the testing cycle.
-
test #
|
on time
|
Stopped moving
|
offTime
|
Moving
time
|
recording start
|
09:47:46
|
|
|
|
1
|
9:53:50
|
9:54:24
|
9:56:46
|
34
|
2
|
9:59:04
|
9:59:49
|
10:02:31
|
45
|
3
|
10:04:44
|
10:05:22
|
10:08:48
|
38
|
4
|
10:11:03
|
10:11:37
|
10:13:51
|
34
|
recording stop
|
10:15:57
|
|
|
|
-
- I would have assumed that the moving time on startup would
have been constant.
Processing the data.
- The 1690 seconds of spectral data was input.
- PolA and B were averaged for each second.
- dynamic spectra were made by flattening the spectra with
the median spectra.
- The dynamic spectra were smoothed/decimated by a factor of
2 in time (to 2 second resolution)
- For the entire freq range:
- the freq was smoothed/decimated by a factor of 6 giving
1365 freq channels of 126Khz resolution.
- The spectral blowups took 34 MHz junks (1600 channels)
with no frequency smoothing (21 KHz resolution)
- horizontal colored lines were drawn on the images to show
when transitions occurred.
- Green: off to on
- Yellow: camera stopped moving
- red : camera turned off.
The dynamic spectra.
The table shows the full scale and blown
up dynamic spectra.
Freq Range
MHz |
dynamic spectra
|
Notes
|
2184-2356 (entire band)
|
.jpg
|
The rfi at the edges are probably aliases
from strong sources outside the rf filter 2200-2345MHz (more
info)
|
2188-2221
|
.jpg |
|
2221-2255
|
.jpg |
|
2255-2288
|
.jpg |
|
2288-2322
|
.jpg |
2305-2315: wcs
2320-2324:siriusxm sat
|
2322-2355 |
.jpg |
2320-2324:siriusxm sat
2328-2336:siriusxm sat
2341-2345:siriusxm sat
|
Summary 24aug22:
- We did not see any rfi at sband that followed the on,off
cycle of the test.
- We need to next test the camera the the12meter site,
with the entire system connected (power over ethernet
cable).
- The freq range of the current 12meter warm receiver
limited the frequencies that we could check.
processing: x101/220824/testcamera.pro
26aug22: moveable camera mounted
at 12meter pad.
On 26aug22 a second set of experiments was
done with the 12meter and the moveable surveillance camera.
The camera was placed at the south west portion of the 12meter
cement slab (in front of the old camera location). Data was
taken at sband and xband.
Setup:
- The camera was placed at the southwest edge of the 12meter
cement slab (in front of the old camera).
- The 12meter telescope was rotated to az=217, el=6 to
point at the camera.
- The receivers used:
- sband receiver was used for the first set of
measurements. The center freq was set to 2270 MHz.
- the xband receiver was used for the 2nd set of
experiments covering about 1 Ghz of bandwidth.
- The mock spectrometer was used to record the spectra:
- sband:
- 1 mock box, 172.032 MHz bw, 8192 channels, pola,b, 1
second integrations.
- xband
- 7 moc boxes, 172.032 MHz bw , 8192 channels,
pola,b , 1 second integrations.
- the data recording was started on a 1 second tick
and ran continuously during each test (sband then xband).
Testing procedure:
Felix turned on and off the camera using about
a 2 minute cycle.
- To turn on the camera he had to open the huffman, turn on the
power and the close the huffman box
- After turning on the camera it would move in azimuth and
elevation for about 40seconds.
- To turn off the camera, the huffman box had to be opened to
shut off the power.
- The test cycle was:
- turn on the camera, report time
- report when moving stopped
- turn off the camera and report time
- The tables below shows the testing cycle.
-
Sband test
test #
|
on time
|
Stopped moving
|
offTime
|
Moving
time
|
recording start
|
8:53:00
|
|
|
|
1
|
8:55:08
|
8:55:53
|
8:57:59
|
45
|
2
|
9:00:05
|
9:00:48
|
9:02:10
|
43
|
3
|
9:04:15
|
9:05:00
|
9:06:43
|
45
|
4
|
9:08:46
|
9:09:29
|
9:10:48
|
43
|
recording stop
|
9:10:56
|
|
|
|
-
-
Xband test
test #
|
on time
|
Stopped moving
|
offTime
|
Moving
time |
recording start
|
9:11:47
|
|
|
|
1
|
9:13:55
|
9:14:39
|
9:16:05
|
|
2
|
9:18:10
|
9:18:54
|
9:20:13
|
|
3
|
9:22:21
|
9:23:06
|
9:24:25
|
|
4
|
9:26:29
|
9:27:12
|
9:28:34
|
|
recording stop
|
9:28:44
|
|
|
|
Processing the data.
- sband:
- 1013 seconds of data,
- 1 file was input
- xband:
- 1018 seconds of data
- 7 files were input (one for each freq band)
- for each file:
- PolA and B were averaged for each second.
- dynamic spectra were made by flattening the spectra with the
median spectra.
- The dynamic spectra were smoothed/decimated by a factor of 2
in time (to 2 second resolution)
- sband:
- For the entire freq range:
- the freq was smoothed/decimated by a factor of 6 giving
1365 freq channels of 126Khz resolution.
- Images with blowups in freq were also made:
- 34 MHz junks, (1600 channels) with no frequency smoothing
(21 KHz resolution)
- Xband
- dynamic spectra for each 172 MHz freq band was made with
126Khz resolution (no blowups in freq).
- For each dynamic spectra:
- horizontal colored lines were drawn on the images to show
when transitions occurred.
- Green: off to on
- Yellow: camera stopped moving
- red : camera turned off.
The dynamic spectra:
the tables below show the dynamic spectra for
the sband and xband measurements.
dynamic spectra
band center freq
|
rcvr
|
dynamic spectra
|
Notes |
2270 (entire band) |
sb
|
.jpg
|
rfi seen above yellow line after camera has
stopped its 1st move sequence. |
8223
|
xb
|
.jpg
|
no camera rfi seen
|
8363
|
xb |
.jpg |
no camera rfi seen |
8505
|
xb |
.jpg |
no camera rfi seen |
8647
|
xb |
.jpg |
no rcamera fi seen |
8789
|
xb |
.jpg |
no camera rfi seen |
8931
|
xb |
.jpg |
no camera rfi seen |
9073
|
xb |
.jpg |
no camera rfi seen |
Summary 26aug22 at 12meter pad
- sband:
- continuum rfi was seen in the sband receiver.
- it started a few seconds after the 45 second move.
- felix had noted that after the 45 second initial move there
was a period of about 30 seconds when the camera sat still and
then is did another short sequences of moves. the rfi looks
like it is occurring during this 30 seconds when the camera
sits before the final move.
- I wonder if the camera is trying to report back via ethernet
that it has completed its startup up?
- This test did not include the fiber optic transceiver that
will go from the ethernet switch out to the rest of the world.
- xband
- No camera rfi was seen in the xband receiver.
processing: x101/220826/testcamerasb.pro,testcameraxb.pro
31aug22: camera mounted on 12meter
control building
On 31aug22 a stationary camera was
placed on top of the 12meter control building and an rfi test was
done (the previous tests used a camera with a motor that could
point in different directions). Data was taken at sband and xband.
A number of tests were done:
- test#1: sband
- huffman box power switched on,off (this also powered
on,off the camera).
- the fiber media converter in control building was left on.
- test #2: xband
- huffman box power switched on,off (this also powered on,off
the camera).
- the fiber media converter in control building was left on.
- test #3: sband
- media converter in control room and huffman box
powered on,off
- test #4: sband
- huffman box, median converter left off
- ethernet switch in control building switched on,off.
Setup:
- The camera was placed on the roof of the 12meter control
building.
- A fiber and power cable went from the control room to the
huffman box.
- the huffman box:
- had a media converter fiber to copper.
- Power over ethernet was then sent to the camera.
- in 12meter control room:
- a media converter went from fiber to copper.
- The copper ethernet was plugged into a multi port ethernet
switch. A fiber cable exited the switch and went down to the
ao Network.
- photos:
- The 12meter telescope was rotated to az=0, el=6 to point
at the camera.
- The receivers used:
- sband receiver with center freq of 2270MHz.
- xband receiver 7x172MHz bands covering 8135 to 9150
MHz.
- The mock spectrometer was used to record the spectra:
- sband:
- 1 mock box, 172.032 MHz bw, 512 channels,
pola,b, .2 second integrations.
- xband
- 7 mock boxes, 172.032 MHz bw , 512 channels, pola,b
, .2 second integrations.
- the data recording was started on a 1 second tick and
ran continuously during each test.
- The 512 channels was a mistake, I really wanted 8192
channels
- the rbw was 336Khz instead of 20Khz. This will make total
power rfi stand out better in the images, but narrow tones
will be harder to see.'
- the .2 second spectra were integrated to 1 sec before
display.
Testing procedures:
Felix turned on and off equipment with a 2 on,
2minute off cycle.
- Test1: sband: huffman box power on,off with 2
minute cycle
- 09:10:13 to 09:31:11
- mock file .00000
- 5 cycles
- on 2 minutes, off 2minutes
- (but we started with camera on rather than camera off)
- The media converter in the control room was left on
- Test2: xband: huffman box power on,off with 2 minute cycle
- 09:33:14 - 09:51:28
- mock file: 00100 .. 7 bands
- 4 cycles
- on 2 minutes, off 2 minutes
- started with an off.
- the media converter in the control room was left on.
- Test3: sband:media converter and huffman box power on,off with
2 minute cycle
- 09:56:25 to 10:12:50
- mock file 00200
- 3 cycles
- on media converter
- 1 minute later huffman box on
- 1 minute later both off for 2 minutes.
- Test4: sband: huffman box off, media converter off, cycle
ethernet switch in control room on,off.
- 10:13:37 to 10:28:17
- mock file .00300
- 3 cycles
- switch on 2minutes
- switch off 2minutes
- started with an off.
Processing the data.
test#
|
rcvr
|
records
(.97secs each rec)
|
mock file
number
|
notes
|
1
|
sb
|
1290
|
0
|
huffman box on,off
|
2
|
xb
|
1124
|
100
|
huffman box on,off |
3
|
sb
|
1009
|
200
|
huffman box on,off & media converter
|
4
|
sb
|
900
|
300
|
network switch on,off
|
- for each file:
- PolA and B were averaged for each second.
- dynamic spectra were made by flattening the spectra with the
median spectra.
- The dynamic spectra were smoothed/decimated by a factor of 2
in time (to 2 second resolution)
- the freq was blown up by 2 to give 1024 pixels.
- For each dynamic spectra:
- horizontal colored lines were drawn on the images to show
when transitions occurred.
- Green: off to on
- red : on to off.
The dynamic spectra:
the tables below show the dynamic spectra for
the sband and xband measurements.
dynamic spectra
test
|
rcvr
|
band center freq
|
dynamic spectra
|
Notes |
1
|
sb
|
2270
|
.jpg
|
huffman box on,off
|
2
|
xb
|
8223
|
.jpg
|
huffman box on,off |
8363
|
.jpg |
there is a standing
wave in freq.. about 12 Mhz
spacing. It drifts to higher freq during the test.
This would be a reflection spacing of 12.5 meters if n=1.
|
8505
|
.jpg |
8647
|
.jpg |
8789
|
.jpg |
8931
|
.jpg |
9073
|
.jpg |
3
|
sb
|
2270 |
.jpg
|
huffman box and media converter on,off
|
4
|
sb
|
2270 |
.jpg
|
network switch in control building on,off
|
Summary 31aug22 camera on top of control
building
- No rfi was seen from the camera, huffman box, media converter
or network switch.
- The channel width was 336 KHz so narrow birdies might not have
been seen.
processing:
x101/220831/testcamerasb.pro,testcameraxb.pro,testcamera_mc_sb.pro,testswitch.pro
221102 testing new camera on top of control
building
On 02nov22 a new cameras was installed on top
of the 12meter control building for rfi testing.
Setup:
- camera in huffman box on top of control building
- fiber and acline -> inside control building.
- 12m: sband, cfr 2270
- mocks: 172.032Mhz, 8192 channels, 1 sec dumps.
Datataking:
- Start the mock spectrometer running (file:
x101.20221102.b0s1g0.00100.fits
- off for 2 minutes (pull the ac power in the control building)
- on for about 3 minutes. leave 2 minutes after video appeard.
- cycle off,on 3 times.
The image shows the dynamic spectra taken while
cycling the camera (.jpg)
- xaxis:
- 172.032 Mhz bw/8192 chan=20Khz. The image was then smoothed,
decimated by 5x (100Khz) to fit on the screen.
- yaxis:
- the time was smoothed, decimated by 2 to fit on the screen
giving 2 sec resolution.
- The green line shows the start of camera off
- the red lines shows the start of camera on
- the video usually appeared 53 seconds after power on
Summary 221102:
- no rfi connected with cycling the camera was seen using 2
second time resolution and 100Khz freq resolution.
processing:x101/221102/testcamerasb.pro
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