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Australia Telescope Users Committee
Technologies Report - Nov 2007
• 7mm Upgrade
• Spare 3/7/12mm receiver for Compact Array
• Spares for upgrading Mopra
• Pulsar Digital Filter Bank
• 13mm receiver for Parkes
• Pulsar Digital Filter Bank for others
• Compact Array Broadband Backend
• 20/13 and 6/3cm upgrade
7mm Upgrade - Array outfitted and science being done.
Spare 3/7/12 mm receiver installed on the Array.
With 3 mm calibration signal injection
7mm spares for Mopra upgrade
Completed for Narrabri staff to refit by March 2008
Pulsar Digital Filter Bank
-PDFB2 at Parkes with 1 GB bandwidth
and proving to be a valuable tool.
-Some trade off between the multibit
digitisation and sensitivity to impulsive
noise sources. These have less impact
when using one bit digitisation.
-PDFB3 is anticipated to be functional
by mid December and will have a
capability for dealing with the impulsive
noise.
-April 2008 is the planned date for
engineers, visiting from overseas
observatories, to construct their own
replicas of the Parkes system.
Parkes 13mm Receiver
- Dewar components have been
assembled and leak tested to prove the
vacuum integrity of the package.
- Control and monitor electronics for the
receiver is near complete. Control and
monitor electronics for the conversion
and local oscillator chain is on track for a
late Nov / early Dec finish.
- Conversion system and local oscillator
chain are both prototyped and the
mechanical design of their housings are
underway for submission to the
workshop.
- Integration of these elements into the
dewar framework will be designed after
their mechanical design is complete.
-Feb 2008 is the planned installation.
Compact Array Broadband Upgrade – CABB
Position
We are not in a position to recommend the changeover to CABB at the
planned date of May 2008.
It was anticipated that by now 2 to 3 antennas would be outfitted and
useful information on system problems might have been encountered
and solutions to these in the pipeline. Not being in that position makes
it is too much of a risk to commit to the planned changeover. Until that
occurs it is difficult to estimate when it would be suitable to make the
swap.
Compact Array Broadband Upgrade – CABB
Problems:
Generally, the use of latest technology has resulted in difficult
challenges.
More specifically, a redirection of effort was required to attend to:
-faults with supplied commercial equipment that delayed manufacture
of printed circuit boards.
-bugs in the tools used to develop the newly released models of
FPGAs and the like. ‘Is it me or is it them’ doubts led to excessive
development effort.
- difficulties in the fabrication of the CABB board due to its complexity.
Compact Array Broadband Upgrade – CABB
Some success
PCBs are being made with the newly setup fabrication lab. CABB DSP boards
have been made but they represent the upper limit in complexity of board that
can be made.
Optical to electronic
scheme
Conversion
sampling
Local
oscillator
distribution
(antenna)
Electrical to
optical
scheme
WDM
Optical to electronic
scheme
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
Optical to electronic
scheme
Optical to electronic
scheme
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
Conversion
Optical to electronic
scheme
sampling
Local
oscillator
distribution
(antenna)
Electrical to
optical
scheme
WDM
Conversion
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
RTM
DSP Board
DSP Board
RTM
Advanced Telecom Compute Architecture (ATCA) rack
32 MHz
distribution
Local oscillator
distribution
(Control building)
Local
oscillator
distribution
(antenna)
WDM
WDM
WDM
WDM
WDM
WDM
On antenna tests of
equipment has
resulted in signals
being locked and
transmitted through
the conversion box,
digitiser, signal
transport and
detected at the
output of the RTM
allowing a spectrum
to be formed.
Conversion
Patch
Panel
sampling
Electrical to
optical
scheme
Optical to electronic
scheme
Some success
WDM
sampling
Electrical to
optical
scheme
WDM
Local
oscillator
distribution
(antenna)
Compact Array Broadband Upgrade – CABB
Some success
A test system in the
Marsfield labs is
almost complete.
Compact Array Broadband Upgrade – CABB
Some success
End of 2007 is a realistic timeframe to have three antennas outfitted with the
interim single frequency CABB equipment, mounted off the pedestal and
operating in parallel with the current system.
Compact Array Broadband Upgrade – CABB
Options
Given the history of the project it is difficult to predict when the full
changeover can occur without having information from tests with three
antennas. Our current best estimate is October 2008.
One option is to outfit five antennas with antenna racks the interim single
frequency CABB equipment operating in parallel with the current system. It is
thought this could be achievable in May 2008 and would provide opportunities
for observing with CABB during the winter season without the loss of current
functionality.
This option means some extra work predominantly for Narrabri staff who
have been consulted and believe they have the resources to accomplish the
tasks required.
20/13 and 6/3cm broadband upgrade.
• The redesigned OMT fins have corrected polarisation asymmetry at the high
frequency end of the 20/13cm band. Further replacement units (end caps,
probes and fins) are being made in pairs and will be installed sequentially.
The next pair should be ready by mid December 2007.
• A priority task is to have ready the new conversion systems, required to
ensure the existing receiver outputs are compatible with the CABB backend,
ready for mid 2008. Procurement of components is underway however the
timelines are tight if this is to integrate with the installation of CABB. A
technical position is to be filled to assist.
• A Narrabri site interference survey has been completed to assess the
spectral content of the frequency bands that are to be used. Consideration
now has to be given to the efficacy of producing amplifiers that extend into
high interference regions of the 20/13cm band.
• Report conclusion
It seems that there may be some need to seriously look as to what
benefits will be won, by going below 1200MHz, from the existing system, when mobile base station
transmitters and impulsive beacons residing around 960-1215MHz exist.
L_Band Measurements
-45
-50
-55
-60
Level[dBm/3MHz]
-65
-70
-75
-80
-85
-90
-95
-100
-105
-110
0
500
1000
1500
2000
2500
Freq[MHz]
Post RT Amps
Pre RT Amps
Spec An Noise Floor
3000
3500
4000
eVLBI and EXPReS
On 28 August, eVLBI was demonstrated live at the APAN meeting in Xian
China. It involved Mopra, Shanghai and 3 telescopes in Europe, all
correlated on the JIVE hardware correlator in the Netherlands. Data
rates achieved were 256 Mbps. 3C273 was observed and for a short time
(all observations were <1 hour). With a 12304 km baseline (Mopra to
Darnhall) it claimed the longest eVLBI on Earth. The press release
was picked up internationally (slash/dot) and made The Australian
locally. Best publicity we've ever had.
On 7 October, the 3 ATNF antennas were connected to the JIVE
correlator with 1 Gbps dedicated lightpaths. The ATNF antennas
operated at 512 Mbps data rates and a full 12-hr observation was
performed and correlated in real time at JIVE. An image of SN1987A
was made with an ~100milli arc second beam at 12cm. A paper is in
preparation.
This work completes the contractual commitments under the EXPReS
proposal. However, a 1Gbps connection to Europe will be retained and
further eVLBI tests will continue.
MMIC Developments
• The project that laid the groundwork for MMIC developments has come
to an end with the termination of the MNRF funding.
• CMOS process receiver on a chip development will continue under the
ASKAP development
• Uncertainty introduced by dealings with TRW and the dwindling
support base in the ICT centre has prompted investigations into a
different process which uses GaAs substrates with InP performance
called ‘metamorphic HEMT’ or MHEMT. Circuits have been designed and
manufactured and await ‘on wafer’ testing.
• Some funding has been set aside in recognition of the possibility for
further investigations or involvement in the field.
Other considerations
• WVRs in the planning stage
• Mopra multibeam study
• 115GHz upgrade
• FPA for Parkes
2007
2008
2009
ATCA 7mm upgrade
7mm upgrade for Mopra
Parkes 13 mm receiver
PDFB3
PDFB external contracts
CABB
20/13 and 6/3 cm upgrade
ASKAP
eVLBI
Water Vapour Radiometers
CA Upgrade to 115 GHz
Mopra Multibeam
FPA for Parkes
Study
Fabrication
2010
2007
2008
2009
ATCA 7mm upgrade
7mm upgrade for Mopra
Parkes 13 mm receiver
PDFB3
PDFB external contracts
CABB
20/13 and 6/3 cm upgrade
ASKAP
eVLBI
Water Vapour Radiometers
CA Upgrade to 115 GHz
Mopra Multibeam
FPA for Parkes
Study
Fabrication
2010
Mopra 3mm
Compact Array 3mm