The installation of the 6 GHz methanol multibeam (MMB) receiver at Parkes in January was the culmination of a concerted effort by members of the Receiver section of the Engineering Development Group and the painstaking workmanship of Marsfield workshop staff.

Graham Moorey led the team that collaborated with a team at Jodrell Bank Observatory and took the Jodrell Bank supplied low noise amplifiers and conversion modules, measured and modified them to improve their performance and built them into a world class seven beam system.

There were hiccups along the way, one that needed a substantial redesign, but these were overcome rapidly, thanks to Pat Sykes and the workshop efforts. Pat gave a new 3-D drawing package its first real challenge in designing the dewar and its internal components, the dewar mounting hardware and cable snake. The tight packing of the input waveguide components made the layout and cable routing a bit of a headache. It all managed to fit together nicely and then the redesign reared its ugly head and it was made to fit together nicely again.

The new 6 GHz Methanol Multibeam (MMB) receiver at Parkes
(click on image for larger version). Photo: Russell Bolton

Alex Dunning's great talent in waveguide component design was once again invaluable in producing the orthomode transducer, needed to extract both polarisations from the signal, and the calibration noise coupler. It was a new challenge working in square waveguide for a lad more accustomed to rectangular and circular cross sections.

Les Reilly's complex, yet ever reliable, electronics worked a treat and some of the credit for that must go to Jennie Lie for her soldering and cabling efforts.

Other expertise in construction and measurement was contributed by Henry Kanoniuk, Russ Bolton, George Graves, Peter Axtens and Daniel Gain. New boy on the block, Paul Doherty, proved his worth with his machining skills complementing those of Eliane Hakvoort.

Graham Moorey was not only Project Leader, but led by example at project's end by rolling up the sleeves and helping in the fabrication of the countless cables required with a cast of thousands.

The "in lab" receiver measurements returned noise temperature measurements in the low 20 K region for all channels and this seems to have been replicated in the "on telescope" measurements. Parkes is now equipped with another powerful tool for generating more great science. See the separate report by Jim Cohen on the commissioning of the MMB.

Graeme Carrad
(Graeme.Carrad@csiro.au)