MIT lincoln labs wideband feed


15may13: rfi scan
17may13: pointing patterns
18may13: rfi from power on,off transceiver and switch.
20may13: rfi az swing

Intro  (top)

  lincoln labs  is bringing a wideband feed to do some tests with arecibo.

Plotting the feed focus vs frequency (.ps) (.pdf)

15may13 rfi scan using spectrum analyzer (top)

    The output of the mit lna was connected to an agilent spectrum analyzer. Data was then acquired from 150 MHz to 3 GHz to look at the rfi environment.
The setup was:

The plots show the measured spectrum from 150 MHz to 3 Ghz using the mit feed and lna's (.ps) (.pdf)
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17may13 Pointing patterns on quasars and gps satellite  (top)

    The mit equipment tracked 2 quasars and one gps satellite on 17may13.
The plots show the az,za positions for each pattern (.ps) (.pdf):

The table below has the timestamped telescope positions for each pattern (and 3 minutes on each side of each pattern)
start tm ast
3C48 pattern 1
3C48 pattern 2
3C138 pattern 1
3C138 pattern 2
gps satellite

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18may13: rfi from mit power on ,off switch  (top)

    The lincoln lab  equipment in the dome could  be turned on, off remotely. After each experiment, the equipment was turned off to not affect other observers. They did this with a  power strip that was controlled via Ethernet. The setup was:
On 17may13 other users reported strong rfi in some of their alfa and lband wide data. The problem was:
On 18may13 around 11:am  the 10 ghz transceiver and Ethernet switch were powered off.
The dynamic spectra (taken with lbw) show the change in the band when the transceiver & switch were power off:

The next plots show how strong these birdies were (.ps) (.pdf):


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20may13 rfi azswing (top)

    An azimuth swing was done on 20may13 starting around 9:30 ast  to look at rfi using the lincoln lab wideband feed. The setup was:

The plots show the measured spectra during the az swing (.ps) (.pdf):
The table below has the telescope positions:
hh:mm:ss start (AST)
azswing az=10deg

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