Australia Telescope Users Committee Technologies Report - Nov 2007

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

-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.

Pulsar Digital Filter Bank

- 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.

Parkes 13mm Receiver

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.


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.


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.

Local oscillator distribution (Control building)

Advanced Telecom Compute Architecture (ATCA) rack

Conversion

sampling

Electrical to optical schemeLocal

oscillator distribution (antenna)

Patch Panel

32 MHz distribution

Optical to electronic scheme

RTM DSP Board


RTM DSP Board

RTM DSP Board

RTM DSP Board

DSP Board RTM

DSP Board RTM

DSP Board RTM

DSP Board RTM


RTM DSP Board


RTM DSP Board

RTM DSP Board

RTM DSP Board

DSP Board RTM

DSP Board RTM

DSP Board RTM

DSP Board RTM


RTM DSP Board


RTM DSP Board

RTM DSP Board

RTM DSP Board

DSP Board RTM

DSP Board RTM

DSP Board RTM

DSP Board RTM

WDM

Conversion

sampling


oscillator distribution (antenna) WDM

Conversion

sampling


oscillator distribution (antenna) WDM

WDM

WDM

WDM

WDM

WDM

WDM

Conversion

sampling

Electrical to optical scheme Local

oscillator distribution (antenna)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.

Some success


Some success

A test system in the Marsfield labs is almost complete.


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.


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

-110

-105

-100

-95

-90

-85

-80

-75

-70

-65

-60

-55

-50

-45

0 500 1000 1500 2000 2500 3000 3500 4000

Freq[MHz]

Le

ve

l[d

Bm

/3M

Hz]

Post RT Amps Pre RT Amps Spec An Noise Floor

eVLBI and EXPReS

On 28 August, eVLBI was demonstrated live at the APAN meeting in XianChina. 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 2010

ATCA 7mm upgrade

7mm upgrade for Mopra

Parkes 13 mm receiver

PDFB3

PDFB external contracts

CABB

20/13 and 6/3 cm upgrade

ASKAP

Water Vapour Radiometers

CA Upgrade to 115 GHz

Mopra Multibeam

FPA for Parkes

Study Fabrication

eVLBI

Mopra 3mm Compact Array 3mm

Australia Telescope Users Committee Technologies Report - Nov 2007

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