Miscellaneous devices
24mar13:Mapping
screen room birdie strength to detectability on the telescope
Links to different devices:
09aug16: BU all sky imager in
antenna test range.
18sep15:uprm
gps station (to put on helipad). luis's document (.pdf)
12jun15: anritsu 3692c
synth in if/lo cabinet in the dome
09jun15: anritsu mg3692c synth
used to replace upstairs 1st lo. rfi measured in screen room.
31jul14:Sick dl100
distomat measured in screen room
31jul14: video
camera measured in screen room
07may14: problems with
Claro cell phone towers in utuado.
22jan14: novatel gps antenna
and receiver (for jade morton) measured in the screen room.
21may13: lidar
xband radar
03apr13:
netgear gsm7238fs network switch. Measured 17oct12 by luis in the
screen room.
01apr13:
netgear prosafe gs110tp network switch. Measured 06sep12 by luis
in the screen room
01apr13:
netgear prosafe gs110t network switch. Measured 16oct12 by luis in
the screen room
31mar13: Softek ivuloto
device at visitors center. measured 15oct12 by luis in the screen
room.
23mar13:ELO model esy15e1 touch
screen cash register for cafeteria
10aug12:
hyperom T4205 Credit card terminal (luis quintero) (.pdf)
- This is the ivu-lotto that people type on at cafeteria, carmen
torres office, and visitors center.
20jan12:
corcom
ac power line filters
05dec11: vlfant at optical lab, azswing freq with
freq near 1400.
AC units atop buildings I,II.
TR electronics distomat:
15feb13:
LB65-00600 distomat measured in screen room
15,23jun11:
Trelectronics
distomat (LLB500-00600) in screen room.
06apr11:TRelectronics
distomant
(LLB-60-d) rfi in screen room.
apr11:Compressor monitor
system.
mar11:iLon smartserver 2000 (AC
control)
mar-apr11:Accurange
3000
laser ranger
oct06:axis 212 ptz web camera.
Devices that have
not yet been added:
- 10aug12: ;hpercom t4205 credit card terminal (have luis's
plots, need mine)
- 20oct11 - fire suppression box. angel made some jpeg files.
- 20120727 ups for sband. luis had pictures and data
- 120618: security camera for 12meter telescope. luis has plots
and data
- 120214, 120315.. previous data on the camera.luis plots and
data.
- 7jul11: rfi test for led lights. luis has data and plots
05dec11: vlf antenna from SRI.
Robert Sparr from SRI brought a vlf system to
study spherics from lightning flashes in venezuela. The system
consisted of:
- vlf antenna
- gps receiver
- active loop vlf antenna
the equipment was enclosed in plastic boxes. In the control room we
checked out the devices and found that the vlf antenna generated a
strong birdie around 1400 Mhz (the gps receiver had other birdies).
We used this frequency to test if any rfi from the system got into
the lbw reciever.
02nov11: test system on top of
antenna test lab adjacent to the lidar lab.
The
system was placed on top of the antenna test shack near the lidar
lab. Setup and acquisition was:
- interim correlator, 195 Khz bw with 2048 channels, 9 level
giving 95 hz Resolution (190 hz after hanning smoothing). 1
second sampling.
- lbw, with linear polarizations centered at 1400 Mhz.
- The acquisition Sequence was:
- turn on system in plastic box.
- Take data
- Turn system off at 228 secs.
- Move vlfant into huffman box (but cables came out the top,
so the box was not securely closed and the cables were not
filtered).
- Turn system back on
- turn system off at sec 491.
The dynamic
spectra show the data during the acquisition (.gif):
- The birdie is seen at 1400 Mhz till the device was turned
off at 228 seconds.
- After placing the vlfant in the huffman box and turning it
back on, the birdie moved to 1399.9949 Mhz (it moved by 5100
hz). 1399.9949 was the frequency we saw the birdie in the
control room.
- The 1399.9949 birdie disappears at 491 when the device is
switched off.
- a Birdie at 1399.981 Mhz pops up every time the vlf antenna
is powered on.
The plots shows the
average spectra (.ps) (.pdf):
- top: spectral average for records 10-200 where the vlfant
was on outside the huffman box. The channel resolution was 190
hz. The 1400 Mhz birdies was 1.4 times Tsys.
- Bottom: spectral average for records 310-460 when the vlfant
was in the huffman box (but not closed correctly). The 1400
Mhz birdie is no .7*Tsys while the 1399.995 birdies is about
40% of Tsys. The 1399.981 birdie is less than 5% (since it was
only on for a short period of time).
05nov11: vlf antenna at offsite location.
The vlf antenna was moved to an offsite location
(jim brakeall's (sp?) ham radio site about 1 mile away). The
antenna was turned on without using the huffman box. Azimuth swings
were done do check the rfi. The setup was:
- az 270-630 degrees at .35 deg/sec. a clockwise (CW) and then
counterclockwise (CCW) swing was done.
- lbw was setup for linear polarization centered at 1398.99 Mhz.
- the mock spectrometer took data using 8192 channels over 168
Khz bw giving 20 hz resolution. 1 second integrations were done.
- to get rid of the mock birdies close to DC, the rf frequency
was offset by -1.008 (1400-1.008=1398.99 rf center) and then
the digital in the mocks moved the band up by 1.008 so the
center of the band was 1400.0 Mhz. This put the A/D sampling
junk 1.008 Mhz from 1400. Mhz.
Dynamic spectra of the az swings.
- The processing for the images:
- The median bandpass for each swing was computed.
- An 11 order harmonic function was fit to the median bandpass
and then used for the bandpass correction.
- polA and polB were averaged.
- A robust sigma for the images was computed and then the
images were scaled to 8 sigma
- CW
swing.gif
- 1400 Mhz birdie.
- always present. Probably coming from our 100 Mhz
reference.
- 1399.98023 birdie.
- 1400.00000 birdie (must be from the 100 Mhz of station
clock).
- 1400.01425 that drifts down to 1400.01085 over the azwing
- 1400.060 drifting birdie
- CCW
azswing.gif
- 1399.98031 birdie
- 1400.00000 birdie (from 100 Mhz of station clock).
- 1400.01069 976 hz wide. Probably the same as the drifting
birdie in the CW spin.
- 1400.060 birdie no longer drifiting.
The plots shows the azimuth
dependence for the 1399.98 Mhz birdies (.ps) (.pdf):
- Black in the CW swing. Red is the CCw az swing.
- Top frame: the average spectra
- 2nd: blowup around the 1399.98 birdie.
- This shifted by about 80 Hz (4 channels) between the cw and
CCW spins.
- 3rd: az dependence of 1399.98 birdie
- bottom: blowup around strongest part of 1399.98 biridie
- The az dependence repeats so it is outside the dome.
- The peaks are around az=27 and az=37.
Summary:
- vlfantenna:
- The vlfant made rfi when at the lidar lab. Putting it inside
the huffman box (without properly closing it) only shifted the
frequency (this may have been the device changing the
frequency as it powered back up.
- moving to the offsite location:
- 1400 Mhz: probably from station clock since exactly on
1400. vlfant not visible
- 1399.9949 not seen
- 1399.9801 that popped up on startup onsite.
- we did see 1399.9803 and 02 birdies. This may or may not
be the same thing.
- The 1400 birdie we saw in the az swings is from the
station clock (it's stable). the vlfant 1400 Mhz was not
visible.
- So the offsite data is inconclusive since we never cycled
the devices power to see any birdies come and go.
- Other birdies close to 1400 Mhz
- 1400.01069 976 wide and drifts ..
- 1400.060 also drifts. Looks like it is part of
the 1400.01069 birdie (they drift together).
processing:
x101/111205/vlfant.pro, azswing.pro
iLon smartserver (AC control)
The mar11 airconditioning upgrade of building 1,
and 2 included the installation of iLon
smartserver (from echelon). The rfi from these devices was
checked by luis in the screen room. The setup was:
- iLon smartserver 2000.
- agilent E4445A spectrum analyzer, 601 channels, and preamp on.
- 1 MHz to 10 Ghz. I've included the data from DC to 3gHz.
- ETS model 7405 902 probe: magnetic field. resonant freq 1.5
Ghz
- Move the probe around the device looking for maximum value
(spectrum analzyer set to max hold).
The plots show the emi
from the smartserver 2000 (.ps) (.pdf):
- Page 1: spectral density plots Dc to 1500 MHz.
- The different colors show separate measurents. Some plots
have a different resolution bandwidth (making the noise floor
lower).
- The black and red dotted lines show two combs:
- black: 25 MHz comb
- red : 32.9798 MHz comb
- 1000 to 1100 MHz is filled with emi.
- The largest peaks are:
- 625 : 25, 33 mhz comb
- 1125: 25,33 MHz comb
- 1088.3: 33 MHz comb.
- Page 2: 1500 to 3000 MHz.
- The largest repeatable peaks are:
- rfi is visible through 2500 MHz.
- Page 3: a few higher resolution spectra covering 327,430, 800
Rcvrs.
- The spectra with lower noise floor used a higher resolution
spectra.
- 327: there are some 2 to 5 MHz combs
- 430: 2.5-4 MHz comb
- 750:
- 2380: 2375 comb visible.
Summary:
- The ac unit has a 25 and 33 MHz comb (32.9798)
- The combs extend thru 2500 MHz.
- The largest peaks are:
- 625.0 : 25, 33 mhz comb
- 1125: 25,33 MHz comb
- 1088.3: 33 MHz comb.
- The 327, 430 and 700 MHz bands also show some 2 to 5 MHz
combs.
processing: x101/110406/doac.pro
Accurange 3000 distomat:
The accurange
3000
distomat was being tested to replace the laser rangers.
On 06apr11 an accurange 3000 laser was tested by luis
quintero in the screened room using a probe and spectrum
analyzer. The setup was:
- Accurange 3000 sitting out in the screen room (no
huffman box).
- agilent E4445A spectrum analyzer, 601 channels, and preamp on.
- 1 MHz to 10 Ghz. I've included the data from DC to 6 gHz.
- ETS model 7405 probles:
- 902:magnetic field. resonant freq 1.5 Ghz
- 903:magnetic field. resonant freq 2.3 Ghz
- 904:electric field: resonant freq > 1Ghz
- Move the probes around the device looking for maximum value
(spectrum analzyer set to max hold).
The plots show the
results of the measurements (.ps) (.pdf):
- Page 1: 902 probe, 0 to 1.5 Ghz.
- top, middle, bottom are 500 MHz sections of 0 to 1.5 Ghz.
- Each color is a separate measurment with the spectrum
analyzer.
- some of the spectra have a lower noise baseline. These have
narrower resolution bandwidths.
- The dotted vertical lines are a comb ath 36.8789 MHz
- The strongest comb birdies are at:
- 295.031 MHz : -66dbm. This repeats for different
measurements.
- 1032.61 MHz : -71dbm, 1069.49 MHz : -74dbm
- Page 2: 902 probe 1.5 Ghz to 6 Ghz
- top,middle, bottom are 1.5 Ghz sections from 1.5 to 6 Ghz.
- There are no obvious birdies that stick out (but these
resolution bandwidths are pretty wide.
- Page 3: compare the response of the 3 probes:
- the colors correspond to the different probes:
- black probe 902 (res freq 1.5 Ghz).
- red probe 903 (res freq 2.3 Ghz)
- green Electric field > 1Ghz.
- probe 902 and then 903 do the best job showing the comb. 904
does not see things above 300MHz.
- this test does not guarantee that the positions of the 3
combs were exactly the same.
Summary:
- The accurange3000 has a comb with a spacing of 36.8789 MHz
- we saw the comb with the probes up to about 1100 MHz.
- The strongest comb elements are:
- 295.031,1032.61,1069.49 MHz.
- probe 902 does the best job showing the probe up to 1.5 Ghz.
processing:
x101/110406/dolaser.pro
Axis 212 ptz web camera:
Sections:
17oct06: looking at the birdies in
the shielded room.
17oct06: rfi from the axis 212 camera seen
through the telescope.
Summary:
Plots:
The
325
and
324 MHz birdies in the shielded room (.ps) (.pdf)
Average of (camera
on)/(camera off) - 1 (on the telescope) (.ps) (.pdf )
Dynamic spectra:
324
MHz
dynamic
spectra: camera in the parking lot (.gif):
324
MHz
dynamic
spectra: camera in the control room (.gif):
325
MHz
dynamic
spectra: camera in the parking lot (.gif):
325
MHz
dynamic
spectra: camera in the control room (.gif):
An axis
212ptz
web
cam is to be installed in the control room and at the
visitor center in oct06. We checked for rfi emissions in the
shielded room and on the telescope. When we made the measurements,
the ethernet was not connected.
17oct06: looking at the
birdies in the shielded room.
The rfi output of the camera was measured in the
shielded room on 17oct06 using the ybt250 (Tektronix) spectrum
analyzer. The small loop antenna was placed close to the lens
of the camera and rotated to give maximum signal.
We found a comb with a 25 MHz spacing
sitting at 300,325,350 etc. MHz. The comb elements seem to be
modulated with about a 100 Khz bandwidth. T
I stepped through 100 MHz to 1500 MHz with a 100
MHz span and then came back and looked at some of the comb elements
with a higher resolution (note: RBW is resolution band width). A
list of some of the more prominent birdies are:
freq |
rbw |
amp (db) |
Notes |
323.997 |
100 Hz |
32 |
Very narrow |
325 |
10 Khz |
25 |
about 100 Khz fwhm |
347.996 |
100 Hz |
32 |
very narrow |
375 |
100 Khz |
20 |
100 Khz fwhm |
400 |
100 Khz |
15 |
|
425 |
1 Khz |
10 |
|
675 |
1 Khz |
15 |
The adjacent noise floor moves down by 15 more db when the
camera is off. |
700
725 |
30 Khz |
25 |
100 Khz wide birdie |
775
800 |
1 MHz |
20 |
|
1375 |
1 Khz |
20 |
adjacent 1374.9 birdie was from repeater |
More Notes:
- The 650-800 MHz was pretty mess. When the camera was powered
off the entire band moved down by about 15 db so there is some
continuum emission.
- Most of the birdies that sat on multiples of 25 MHz had
a FWHM of 100 Khz.
- The narrow birdies at 323.997 and 347.996 were not resolved
with the 100 Hz RBW.
Plots were made of the
325
and
324 MHz birdies in the shielded room (.ps) (.pdf).
The
data
was taken with the loop antenna and the Tektronix spectrum analyzer
in the screened room:
- Top: this is the 325 MHz birdie. with a 10 Khz rbw. It is one
of the stronger comb elements. The black trace has been averaged
by 10 sweeps, the red trace is a peak hold.
- Bottom: The 324 MHz narrow birdie. The rbw was 100 hz. This
narrow birdie was also seen at 347.996 MHz.
processing: x101/061017/cameralab.pro
17oct06: rfi from the
axis 212 camera seen through the telescope.
On 17oct06 we looked at the rfi from the axis 212
camera using the telescope. The setup was:
- Interim correlator with 380 hz resolution (after hanning) 324
MHz and 25 Khz resolution.
- 1 second integrations were taken. During this time we turned
the camera on and off.
- We used the 327 MHz receiver (Tsys about 130K) for the 324 and
325 MHz birdies. lbw (tsys about 28K) for the 1375 MHz birdie.
- The telescope was parked at az=337.2, za=19. This position
gave a maximum when we transmitted from the control room (see az,za
dependence
of
transmitted birdies).
- Data was taken with the camera in the parking lot adjacent to
the control room (in the rfi van). It was also taken with the
camera in the control room on the desk next to the observer2
workstations. These were the same two positions used for the
transmitted birdies test. So hopefully the az,za we picked was
close to a maximum. The only difference would be the field
pattern of the transmit antenna versus the field pattern of the
camera.
The first plots are dynamic spectra for 324 MHz and 325 MHz with the
camera in the parking lot and in the control room. The horizontal
dashed lines surround when the camera was turned off:
- 324 MHz Birdie (narrow band):
- 325 MHz Birdie (100 Khz fwhm). Part of the 25 MHz comb.
The average of
(camera on)/(camera off) - 1 (.ps) (.pdf
) is also plotted. Black has the camera in the parking lot, red
is in the control room:
Top: 25 Khz resolution centered at 325 MHz. The dashed
green lines are the two birdies. You see them in the parking lot
but not in the control room.
Center: 390 Hz resolution spectrum shows that the narrow
band birdie is at 323.995 MHz. It is 1.5 times Tsys in a 390 Hz
channel when the camera is in the parking lot.
Bottom: blowup of the 390 Hz resolution spectra. You can see a
small bump in the control room (red) spectra about 1 Khz above
the camera birdie. This is probably the streak we saw in the 324
MHz dynamic spectra from the control room. Since the 323.995
birdie remained relatively stable, my guess is that the birdie
we saw in the control room is not coming from the camera.
processing: x101/061017/cam_on_tel.pro
Summary:
- The axis 212 camera has a 25 MHz comb at multiples of 25 MHz.
It is about 100 Khz wide
- Two narrow birdies were seen at 323.995 and 348 MHz.
- Some of the stronger birdies seen in the screen room
were: 324,325,348,375,700,725,1375 MHz.
- With the camera in the parking lot we see the camera birdies
at 323.995 and 325 MHz. The 323.995 birdie is 1.5 times Tsys in
a 390 Hz channel. We do not see the birdie at 1375 MHz.
- With a 100 second integration the 325 and 324 MHz birdies were
not seen in the control room.
- If the camera is placed at the visitors center, it will have
to be put inside a shielded box.
- If the camera is placed in the control room then you probably
can use it without a shielded box. The only question is whether
there is an az,za and camera position that will be much stronger
than the ones we used. If the rfi shielded boxes are not hard
(expensive) to build, it might be a good idea to put all of the
cameras in a box.
home_~phil