jim ruffantennas & feeds pdr 2/12/02 1 antennas & feeds mechanical design feed cone feed...
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Jim Ruff Antennas & Feeds PDR2/12/02
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Antennas & FeedsMechanical Design
Feed Cone
Feed Mounting
Horn Fabrication
Jim Ruff Antennas & Feeds PDR2/12/02
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Feed Cone
• Why?– More Frequencies– RFI Containment– Reduced clutter at antenna vertex
• How?– Similar to existing K/Q segments– Monolithic
Jim Ruff Antennas & Feeds PDR2/12/02
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Feed Circle
Jim Ruff Antennas & Feeds PDR2/12/02
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EVLA Feed Cone
The L-Band horn is not contained in the feed cone.
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Feed Cone
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Feed Cone
• Unresolved Questions– Aluminum or Polycarbonate core?
• Aluminum cores are stiffer
• Polycarbonate cores are better thermally
– Service Access• Receiver heights vary greatly
• Space will be at a premium
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Feed Mounting
• Features:– Based on VLA X-Band– Continuous metal-to-metal for RFI containment– Simple horn installation and alignment– Convenient receiver swapping
• Which Bands?– S? C X Ku K? Ka? Q?
Jim Ruff Antennas & Feeds PDR2/12/02
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Jim Ruff Antennas & Feeds PDR2/12/02
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Feed Mounting
Jim Ruff Antennas & Feeds PDR2/12/02
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Feed Mounting
Jim Ruff Antennas & Feeds PDR2/12/02
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Feed Mounting
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Horn Fabrication
• Laminated Horns (L, S and C)– Similar to VLBA L-Band horns– Reduce weight and simplify construction– Tooling
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Laminated Horns
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Laminated Horns
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Ring Loaded Horns
• A Proposal for Ring Loaded Horns– Simplify assembly– Simplify receiver mounting– Improve flange mate-up reliability– Reduce manufacturing cost
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Ring Loaded Horns