EVLA Feed CDR Outdoor Antenna Test Range OATR
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EVLA Feed CDR Outdoor Antenna Test Range (OATR) Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 1
The OATR: Purpose To support the EVLA Project by providing: • A mechanism to monitor the feed horn manufacturing process by using: – VSWR measurements: All new feeds will be tested! (100% Sampling) – Radiation patterns: Statistical Sampling = 5 or 6 units from each frequency band + the first feed fabricated with new or modified manufacturing process. (~20% Sampling) • A long-term troubleshooting tool! • Future design testing platform. Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 2
The OATR: Why a local facility? Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 3
The OATR: Progress (Highlights) Overall Completion: 51% Requirements: 60% Location: 22 ft Baseline Separation Simulating the distance between the sub-reflector and the feed circle. 14 ft Elevated Platforms To reduce potential multi -path reflection energy. 0. 05 deg Angular Resolution Based on the optical encoder resolution with the systematic backlash of the positioner. 1700 lb Vertical Load Capacity Using double density polystyrene foam tower. Troy A. Jensen Tunable Frequency Range: 45 MHz – 26. 5 GHz Actual Coverage: 1 – 18 GHz Sensitivity: -70 d. Bm Amplitude Repeatability: ~ 1. 5 d. B EVLA Feed CDR - OATR 17 Feb 2005 30% HP 8510 B (Rx) HP 8340 A (Tx) Standard Gain Horn coverage Estimate only! Based on acquired radiation pattern data. Refinement still in progress! 4
The OATR: Capabilities (Generalized) • • • Amplitude and Phase measurements. Time-Gating with pico-second resolution. Gain normalization. Phase Center measurements. Axial ratio / Polarization measurements. Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 5
The OATR: The Site! Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 6
The OATR: Proof of Concept Setup Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 7
(Intentionally left blank) Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 8
The OATR: Progress (Detailed) Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 9
The OATR: Reflections Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 10
The OATR: Boresight (Electrical) Troy A. Jensen EVLA Feed CDR - OATR 17 Feb 2005 11
