HartRAO Home

HartRAO Home > news > 1.3cm Receiver Testing 2006/05/22


1.3cm Receiver Testing 2006/05/22


One of the aims of the upgrade to the surface of the 26-m telescope at Hartebeesthoek that began in 1998 was to extend the upper frequency limit of 12 GHz. The objective was to make the next major radio astronomy band around 22 GHz usable.

Testing of the new surface indicated that this was likely to be the case, so development of a 22 GHz (1.3 cm wavelength) receiver began in 2005. The receiver was completed in 2006 April, and the images below show the receiver under test.

1.3cm receiver rollout 1
Click on image for larger version

Staff admire the new receiver at rollout on 2006 April 11. From the left: Gert Agenbag, Piet Louw, Jonathan Quick, Keith Jones, Roland Huang, Neels Visser, Jacques Grobler, and a quizzical Sharmila Goedhart.

1.3cm receiver rollout 2
Click on image for larger version

Keith Jones keeps a close eye on Jacques Grobler as he works on the calibration noise diode.

1.3cm receiver rollout 3
Click on image for larger version

A portrait of the new receiver in its fetching colour scheme.

1.3cm receiver calibration 1
Click on image for larger version

2006 May 22 and the receiver is on the roof of the workshop to get a good horizon for tipping curves. The air is relatively dry following the passage of a severe cold front. The angled dark box on the left contains eccosorb to act as an ambient load at which the feed can be aimed. The dark blue box below the receiver contains the cold load, which is filled with liquid nitrogen. A hose leads from the liquid nitrogen dewar to the cold load. Jacques Grobler is tilting the receiver to take a tipping curve measurement.

1.3cm receiver calibration 2
Click on image for larger version

Keith Jones provides live voicemail between Jacques and...

1.3cm receiver calibration 3
Click on image for larger version

...Jonathan Quick in the corridor below with the radiometer, who is taking the measurements.

1.3cm receiver calibration day 2 #1
Click on image for larger version

Day two of the calibration and the experimental setup has been altered to bring the loads closer to the receiver. From the left, Piet Louw, Keith Jones and Ben Klein wait as readings are taken.

1.3cm receiver calibration day 2 #2
Click on image for larger version

Closeup of the cold load in the bath of liquid nitrogen.

1.3cm receiver calibration day 2 #3
Click on image for larger version

George Nicolson, with back to camera, and Jonathan Quick consider the numbers.

1.3cm receiver calibration day 2 #4
Click on image for larger version

George takings readings from the radiometer while Jon notes the frequency.