Technical
Mode:Line
Back end:Mixed
Back end Mode:ACR: 1x2, any-level, probably single-bank
Procedures:Mixed
Receiver:Multiple
Switching Scheme:Mixed
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Proposal Information
PI:Braatz
Bands: 3468ALSCXUK
Back ends: S
Support Person: J. Braatz/R. Maddalena
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Checkout Notes
Maybe multi-bank mode will be needed. RFI at lower frequencies.
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Technical
Mode:Line
Back end:SP
Back end Mode:2x1024 5-10 MHz
Procedures:OTFMap
Receiver:L
Switching Scheme:FreqSwitch
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Proposal Information
PI:Lockman
Bands: L
Back ends: SP
Support Person: J. Lockman
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Checkout Notes
Similar to other projects and can be scheduled.
9/5/2 - Meeting on Stray Raditaion [PJ, RP, RM, JL, CB]
The 2A31 observations could be scheduled but their reduction requires that stray radiation calibration be completed first. The following tasks are needed to complete the stray radiation calibration: (a) Obtain an accurate model of the beam pattern (JL to get model from Sri), (b) compare the data already collected with the model and complete the software for calculating corrections, (c) find a student or other help to complete (b) (JL to pursue this avenue), and (d) take further observations for any 'fine tuning'.
Once a time scale is known for completing the determination of the stray radiation calibration the observations of 2A31 will be scheduled.
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Technical
Mode:Line
Back end:ACR200
Back end Mode:1x2, multi-bank
Procedures:DualBeamSwitch
Receiver:K
Switching Scheme:BeamSw
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Proposal Information
PI:Braatz
Bands: K
Back ends: S
Support Person: J. Braatz/R. Maddalena
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Checkout Notes
Can be scheduled since project is similar to Jim's H2O project. Single-bank mode would cose twice the telescope time.
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Technical
Mode:Line
Back end:ACR50
Back end Mode:1x2, 3-level, single-bank or 1x2, 9-level, multi-bank
Procedures:DualBeamSwitch
Receiver:K
Switching Scheme:BeamSw
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Proposal Information
PI:Claussen
Bands: K
Back ends: S
Support Person: G. Langston
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Checkout Notes
Probably 3-level sampling would be fine, in which case multi-bank mode not needed.
03/02/03 G. Langston
These two proposals are similar. They are proposals to observe
galactic water masers observations and are fairly straight forward,
requiring 50 MHz single quadrant spectrometer observations. Have source
lists for the tests, and will require only a short time for checkout.
03/12/03 G. Langston
The test observations for two galactic water maser projects, 02A63 and 02B03,
appeared to be successful. The data have not yet been completely reduced
with AIPS++, but these experiments appear to be straight forward to observe.
These projects can be scheduled.
02A63: Test data in /home/gbtdata/TGBT02A_63_01
Used the same configuration as for 02B03. Did not see lines in quick looks
at V1515CYG, V1057CYG, V1331CYG or V1735CYG. Did see lines in NR01B+C and
DR21.
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Technical
Mode:Line
Back end:ACR200
Back end Mode:2x2, multi-bank
Procedures:DualBeamSwitch
Receiver:K
Switching Scheme:BeamSw
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Proposal Information
PI:Greenhill
Bands: K
Back ends: S
Support Person: J. Braatz/R. Maddalena
|
Checkout Notes
Baselines might be an issue. Single-bank mode not practical since it requires 4x the telesocpe time.
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Technical
Mode:Line
Back end:S
Back end Mode:1W4---200 or 2W4---200 single-bank
Procedures:OffOn
Receiver:C
Switching Scheme:TotalPwr
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Proposal Information
PI:Henkel
Bands: C
Back ends: S
Support Person: D. Balser/J. Braatz
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Checkout Notes
09/26/03 Braatz/Balser
Dana and I successfully ran the checkout today for project 2C20, "A 6 GHz Survey for Extragalactic OH Megamasers". Our checkout data look great, and we feel you can schedule this project any time. Christian Henkel is PI for this project. I'll contact him and send him reduced spectra from today's test run.
FYI, as part of today's test we confirmed the detection of OH at multiple transitions near 5 cm and 6 cm towards Arp220. This source is part of the 2C20 program. The confirmation is of interested since it was detected, seemingly convincingly, at the 140-ft but was not detected when observed at Effelsberg in an attempt to confirm.
Wide lines require good baselines
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Technical
Mode:Line
Back end:S
Back end Mode:No information in proposal
Procedures:Track
Receiver:K
Switching Scheme:Frequency
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Proposal Information
PI:Liszt
Bands: K
Back ends: S
Support Person: R. Maddalena
|
Checkout Notes
Maybe can be scheduled if the bandpasses are small enough.
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Technical
Mode:Line
Back end:S
Back end Mode:1W2--- 800 dual-bank
Procedures:DualBeamSw
Receiver:K
Switching Scheme:BeamSw
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Proposal Information
PI:Kondratko
Bands: K
Back ends: S
Support Person: J. Braatz/R. Maddalena
|
Checkout Notes
Baselines and multi-mode. BeamSw probably better than the proposed TotalPwr
|
Spectrometer (Autocorrelator) Notes
Fall '03
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Technical
Mode:Line
Back end:S
Back end Mode:2W2--200 dual-bank
Procedures:OffOn
Receiver:CXU
Switching Scheme:TotalPwr
|
Proposal Information
PI:Kondratko
Bands: CXU
Back ends: S
Support Person: J. Braatz/R. Maddalena
|
Checkout Notes
Baselines and pastting together of serial spectra.
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Spectrometer (Autocorrelator) Notes
Fall '03
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Technical
Mode:Line
Back end:S
Back end Mode:1W1--- 800 four-bank or 1W2---800 two-bank
Procedures:TP_OTFMapping
Receiver:K
Switching Scheme:TotalPwr
|
Proposal Information
PI:McGary
Bands: K
Back ends: S
Support Person: F. Ghigo/R. Maddalena
|
Checkout Notes
Baselines probably not an issue even with wide bandwdiths. Multi-bank.
06/10/03 F. Ghigo
Project checkouts for projects 02C_052, 03B_011, and 03B_027
were done on May 20th. All of these use the K-band receiver
with 4 IFs of 50 MHz bandwidth. All these projects can be
scheduled (with some slight worries as mentioned below).
Observations were done at 4 frequencies of NH3 transitions,
in source LDN134N. Position switching, nodding, and on-the-fly
mapping was done. Two of the proposals will probably
benefit from double beam-switching (3B_011 and 3B_027).
The other requests mapping.
All of this seems to be working reasonably well. The spectrometer produces reasonable looking spectra both in
single beam (8 samplers) and double beam (16 samplers)
observations. The noise levels were somewhat higher than
theoretical, but the weather was bad and system temperatures
were varying in the range 90-130K, so this is perhaps not
a problem with the spectrometer.
It was not possible to balance the power levels from all IFs at once,
but we put one spectral window at 25.06 GHz, and the
other three in the 23.6 - 23.9 range. It may just not be
possible to balance all windows over that wide a range.
This would be a problem for project 02C_052, which
wants to observe these NH3 transitions. For the other
proposals, the exact transitions were not specified, so we
do not know exactly whether this would be a problem.
So given that the K-band receiver will be undergoing some
improvements over the summer, and that the beam switches
will be working properly, and hoping for improvements in
the dish software for handling multi-IF data, I think
we can go ahead and schedule these projects.
|
Technical
Mode:Line
Back end:S
Back end Mode:2W2--- 200 two-bank
Procedures:DualBeamSw
Receiver:K
Switching Scheme:BeamSw
|
Proposal Information
PI:Braatz
Bands: K
Back ends: S
Support Person: J. Braatz
|
Checkout Notes
Maybe baselines. Multi-bank
|
Technical
Mode:Pulsar
Back end:BC
Back end Mode:
Procedures:
Receiver:8L
Switching Scheme:
|
Proposal Information
PI:Stairs
Bands: 8L
Back ends: BC
Support Person: F, Ghigo
|
Technical
Mode:Line
Back end:S
Back end Mode:4W2---200 single-bank
Procedures:OffOn
Receiver:K
Switching Scheme:TotalPwr
|
Proposal Information
PI:Modjaz
Bands: K
Back ends: S
Support Person: F. Ghigo
|
Checkout Notes
Maybe BeamSw would be more efficient. Probably can be scheduled once the weather gets good.
|
Technical
Mode:Line
Back end:S
Back end Mode:2W2---200 two-bank
Procedures:DualBeamSw
Receiver:K
Switching Scheme:BeamSw
|
Proposal Information
PI:Braatz
Bands: K
Back ends: S
Support Person: J. Braatz/R. Maddalena
|
Checkout Notes
Baseline willprobably be an issue. Multi-bank.
|
Technical
Mode:
Back end:2
Back end Mode:
Procedures:
Receiver:LX
Switching Scheme:Position
|
Proposal Information
PI:Kardashev
Bands: LX
Back ends: 2
Support Person: G. Langston
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:3
Switching Scheme:
|
Proposal Information
PI:Kronberg
Bands: 3
Back ends: S
Support Person: G. Langston
|
Technical
Mode:Line
Back end:PD
Back end Mode:
Procedures:
Receiver:L
Switching Scheme:Frequency
|
Proposal Information
PI:Lockman
Bands: L
Back ends: PD
Support Person: J. Lockman
|
Technical
Mode:Pulsar
Back end:BP
Back end Mode:
Procedures:
Receiver:L
Switching Scheme:
|
Proposal Information
PI:Stairs
Bands: L
Back ends: BP
Support Person: G. Langston
|
Scheduling Notes
(continuation of 2A52)
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:K
Switching Scheme:Position
|
Proposal Information
PI:Swift
Bands: K
Back ends: S
Support Person: G. langston
|
Checkout Notes
10/18/03 G. Langston
The molecular line observations at 23.7 GHz looked very good. The
lines were clearly visible in 5 minute integrations and the baselines
looked good. This project 0319 can be scheduled.
Used the 2 K-band, high-band feeds, for simultaneous NOD and
mapping observations. Did not use the beam-switched mode, as
the baselines looked good with out it. Not using beam-switched
reduces the data volume by a factor of two.
Clearly saw more than 5 NH3 lines toward his source. Made a
6 second integration per sample, 4x4 arc-minute map. Have not
made an image yet. Found that the focus change was more than
desired after a 1 hour mapping run. Should probably focus
at least once every 30 minutes.
Data are in /home/gbtdata/TPCO_3A19
Used the IF Rack optical driver modules 1, 3, 5, and 7 for the
observations, each with 320 MHz filters. Found that the signal levels were
OK, but low at the converter rack output. Had only a few dB of power
margin left for driving the spectrometer with 50 MHz bandwidth spectra.
Would certainly have had trouble observing lines space by more than 320 MHz.
The planned additional Converter Module gain should help this.
Problems
========
Focus and pointing went well on a nearby bright radio source. One problem
was that GO changes the velocity to zero and reference frame to LOCAL
for pointing observations. But does not change them back to
LSR-K and 6.93 km/sec for NOD and RALONGMAP. After the focus, started
the map again. Then discovered that the velocity definition
was wrong and aborted the scan. This lead to a spectrometer hang. After
about 20 minutes, were were back in operation again.
Future GO / configurator should remember the settings for each procedure,
so that switching between observing types is less error prone.
10/15/03 G. Langston
This project may be scheduled.
Attempted to compare the Low K-band R1 and R2 channels, but
the weather variations made detailed comparison difficult.
As far as Mike, Ron and I could tell, both channels appeared
to be equally stable.
The project 03A19 is a High K-band project using the spectrometer
in dual quadrant, 50 MHz dual polarization 9-level mode. The
system was configured for this experiment without too much trouble.
There was plenty of IF power for this experiment, but the system
temperature was nearly 200K.
Ran a few 5 minute OffOn scan pairs and the noise was reducing as
expected with increasing integration time, however with such a
high system temperature, we may not have reached the level
where systematic effects become important. Center frequency
was 23.7088144 GHz.
Challenges
==========
Also tested the K band system for observations configured
for widely spaced (> 1 GHz) molecular lines. Found that
lines separated by 1 GHz could be observed, but had to
set the fiber optic modem target power level to 4 Volts.
At this power level the converter modules had almost no
attenuation inserted. For tests of IF gain, simultaneously observed
HC5N line at 23.963 GHz along with ammonia lines.
Additional converter module gain would be needed for
lines separated by more than 2 GHz.
Found there was 15 dB less power in the L3+Optical Driver
S2 IF chain, than in the R3+S4 IF chain (Also L4 and R4 seemed to
have the same power level as the R3+S4 pair.)
M&C Fix needed
==============
Had to call Melinda in to help with a very annoying M&C problem.
No scans would run because of some strange configuration
problem with "LO1 phase state" data going into the "/home/gbtdata/test"
directory, while all other data was going into the correct
directory /home/gbtdata/TPCO_3A19. Operators and I tried every
manager reset and reconfiguration we could think of before giving up.
We lost over an hour of checkout time because no scans would run,
even though we did not want this LO1 data. The M&C design should
be to "WARN" if data is not going into the correct directory, but
not stop a scan.
This point is true in general, as the GBT system is so large and complicated
a system that often there will be anomalies; but they should not prevent
observations.
02/14/03 R. Maddalena
3A-019: The winds shut Harvey and me down before we could try out any
observing. This proposal want to observe two transitions with both
polarizations ion a 50 MHz band. All we know is that we can get the
appropriate signals into the appropriate Spectrometer samplers.
03/02/03 G. Langston
This proposal requires spectral line mapping with the spectrometer
over a 4 arcminute by 4 arcminute region, at two Ammonia line frequencies,
23.695 and 23.722 GHz. This experiment can be performed with the four
quadrant, 50 MHz bandwidth mode of the spectrometer. Uncertain
of the state of AIPS++ for high resolution spectral line imaging.
03/12/03 G. Langston
The GBT IF/RF can be set up for 03A19 observations, but no lines were seen
in the test sources. There were some software problems with the test
observations, but these were over come. The non-detection may have been due
to a bad choice of test sources, or user error. Further tests are required.
|
Technical
Mode:Pulsar
Back end:P
Back end Mode:
Procedures:
Receiver:L
Switching Scheme:
|
Proposal Information
PI:Stairs
Bands: L
Back ends: P
Support Person: G. Langston
|
Scheduling Notes
(cont of 1A79)
|
Technical
Mode:Pulsar
Back end:B
Back end Mode:
Procedures:
Receiver:8
Switching Scheme:
|
Proposal Information
PI:Becker
Bands: 8
Back ends: BDS
Support Person: G. Langston
|
Checkout Notes
05/19/03 G. Langston
The 800MHz proposal of Becker (03A-025) can be scheduled. Note that
this is actually a BCPM pulsar proposal, not a Spectral Line
observation. The web pages should be updated.
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:K
Switching Scheme:Position
|
Proposal Information
PI:Eisner
Bands: K
Back ends: S
Support Person: G. Langston
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:L
Switching Scheme:Position
|
Proposal Information
PI:Yun
Bands: L
Back ends: S
Support Person: K. O'Neil
|
Scheduling Notes
nighttime (1/4-5/1)
|
Technical
Mode:Pulsar
Back end:B
Back end Mode:
Procedures:
Receiver:L8S
Switching Scheme:
|
Proposal Information
PI:Ransom
Bands: L8S
Back ends: B
Support Person: G. Langston
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:K
Switching Scheme:
|
Proposal Information
PI:Walsh
Bands: K
Back ends: S
Support Person: R. Maddalena
|
Technical
Mode:Pulsar
Back end:B
Back end Mode:
Procedures:
Receiver:LS
Switching Scheme:
|
Proposal Information
PI:Kaspi
Bands: LS
Back ends: B
Support Person: G. Langston
|
Technical
Mode:Pulsar
Back end:B
Back end Mode:
Procedures:
Receiver:L8
Switching Scheme:
|
Proposal Information
PI:Roberts
Bands: L8
Back ends: B
Support Person: G. Langston
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:
Receiver:K
Switching Scheme:Position
|
Proposal Information
PI:Butner
Bands: K
Back ends: S
Support Person: F. Ghigo
|
Checkout Notes
06/10/03 F. Ghigo
Project checkouts for projects 02C_052, 03B_011, and 03B_027
were done on May 20th. All of these use the K-band receiver
with 4 IFs of 50 MHz bandwidth. All these projects can be
scheduled (with some slight worries as mentioned below).
Observations were done at 4 frequencies of NH3 transitions,
in source LDN134N. Position switching, nodding, and on-the-fly
mapping was done. Two of the proposals will probably
benefit from double beam-switching (3B_011 and 3B_027).
The other requests mapping.
All of this seems to be working reasonably well. The spectrometer produces reasonable looking spectra both in
single beam (8 samplers) and double beam (16 samplers)
observations. The noise levels were somewhat higher than
theoretical, but the weather was bad and system temperatures
were varying in the range 90-130K, so this is perhaps not
a problem with the spectrometer.
It was not possible to balance the power levels from all IFs at once,
but we put one spectral window at 25.06 GHz, and the
other three in the 23.6 - 23.9 range. It may just not be
possible to balance all windows over that wide a range.
This would be a problem for project 02C_052, which
wants to observe these NH3 transitions. For the other
proposals, the exact transitions were not specified, so we
do not know exactly whether this would be a problem.
So given that the K-band receiver will be undergoing some
improvements over the summer, and that the beam switches
will be working properly, and hoping for improvements in
the dish software for handling multi-IF data, I think
we can go ahead and schedule these projects.
|
Technical
Mode:Line
Back end:P
Back end Mode:
Procedures:
Receiver:L
Switching Scheme:Frequency
|
Proposal Information
PI:Benjamin
Bands: L
Back ends: P
Support Person: J. Lockman
|
Technical
Mode:Line
Back end:S
Back end Mode:4N4-50-9, 1-bank; 2N2-50-9 2-bank; 1N1-50-9, 4-bank or 1N4-12-9 1-bank
Procedures:Track
Receiver:K
Switching Scheme:Frequency
|
Proposal Information
PI:Bergin
Bands: K
Back ends: S
Support Person: R. Maddalena
|
Checkout Notes
9/5/03 Maddalena - Need to make sure which ACF modes are viable and whhether the BW is 12.5 or 50 MHz.
|
Technical
Mode:Line
Back end:S
Back end Mode:1N-50-9 2-banks; 2N2-50-9 2-bank
Procedures:OnOff
Receiver:K
Switching Scheme:Position
|
Proposal Information
PI:Sahai
Bands: K
Back ends: S
Support Person: R. Maddalena
|
Checkout Notes
9/5/03 - Maybe beam-switching would be advantageous. RMS calcuulation is sqrt(2) too optimistic.
|
Technical
Mode:Line
Back end:S
Back end Mode:Same as before
Procedures:Nod
Receiver:K
Switching Scheme:Position
|
Proposal Information
PI:Braatz
Bands: K
Back ends: S
Support Person: J. Braatz
|
Technical
Mode:Line
Back end:S
Back end Mode:
Procedures:Track - Offset Mode
Receiver:L
Switching Scheme:Frequency
|
Proposal Information
PI:Lovell
Bands: L
Back ends: S
Support Person: R. Maddalena
|
Checkout Notes
9/5/03 Maddalena - Need information on which OH lines will be observered, backen configurations, etc.
|
Technical
Mode:Line
Back end:P
Back end Mode:
Procedures:Other
Receiver:L
Switching Scheme:Frequency
|
Proposal Information
PI:Mayo
Bands: L
Back ends: P
Support Person: K. O'Neil
|
Technical
Mode:Line
Back end:P
Back end Mode:
Procedures:Other
Receiver:L
Switching Scheme:Frequency
|
Proposal Information
PI:Troland
Bands: L
Back ends: P
Support Person: K. O'Neil
|
Technical
Mode:Pulsar
Back end:BS
Back end Mode:
Procedures:Track
Receiver:L8
Switching Scheme:
|
Proposal Information
PI:Jacoby
Bands: L8
Back ends: BS
Support Person: A. Minter/F. Ghigo
|
