Green Bank Telescope Status
Last update: 2 November 2000
The NRAO staff began outfitting the GBT on 2 October, following a provisional acceptance of the antenna from the contractor, Lockheed-Martin. The NRAO now has ready access to the telescope for outfitting and commissioning while the contractor continues to complete items on the "punchlist."
NRAO outfitting has gone extremely well:
- All cables in the Actuator Control Room (27,000 wires!) have been terminated. These connections allow the active surface of 2209 panels to be measured and controlled. The software that reads LVDT position sensors on the actuators has been tested. The next step is to connect the power to the actuator motors.
- Servo equipment for control of the Az / El drives and the Prime Focus and Subreflector drives has been installed.
- All welded cryogenic tubing runs from the compressors on the alidade structure (near ground level) to the Receiver Room (450 feet upstairs) have been completed. Lines are now being evacuated and "cold trapped." The L-Band Receiver began cooling on 1 November.
- Receivers installed to date in the Gregorian Receiver Room include the L, S, C, X, and Ku Band receivers.
- Fiber optic lines that carry control and IF signals have been run and connected to all principal locations (Servo Room, Actuator Control Room, Receiver Room).
Upcoming and on-going work includes:
- Re-installation by the contractor of the motors that actuate the Prime Focus Boom and Subreflector. They are currently being repaired at the manufacturer.
- Completion by the contractor of the alignment of the elevation bull gear.
- Installation of the K-Band Receiver.
- Installation of the Prime Focus 1 Receiver (290 - 920 MHz) following installation of boom actuators.
- Cool-down of all remaining receivers.
Provided the prime focus and subreflector motors are returned in the next week and the bull gear alignment is completed, commissioning of the prime focus receiver will begin on 15 November.