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)
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:

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:
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:
    The dynamic spectra show the data during the acquisition (.gif):
    The plots shows the average spectra (.ps) (.pdf):

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:
Dynamic spectra of the az swings.
The plots shows the azimuth dependence for the 1399.98 Mhz birdies (.ps) (.pdf):


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:
The plots show the emi from the smartserver 2000 (.ps) (.pdf):


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:
The plots show the results of the measurements (.ps) (.pdf):


processing: x101/110406/dolaser.pro

Axis 212 ptz  web camera:

17oct06: looking at the birdies in the shielded room.
17oct06: rfi from the axis 212 camera seen through the telescope.

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.
30 Khz 25 100 Khz wide birdie
1 MHz 20
1375 1 Khz 20 adjacent 1374.9 birdie was from repeater

More Notes:

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:
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: 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: 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