1. Jim RuffAntennas & Feeds PDR 2/12/02 1 Antennas & Feeds Mechanical Design Feed Cone Feed Mounting Horn Fabrication

2. Jim RuffAntennas & Feeds PDR 2/12/02 2 Feed Cone Why? –More Frequencies –RFI Containment –Reduced clutter at antenna vertex How? –Similar to existing K/Q segments –Monolithic

3. Jim RuffAntennas & Feeds PDR 2/12/02 3 Feed Circle

4. Jim RuffAntennas & Feeds PDR 2/12/02 4 EVLA Feed Cone The L-Band horn is not contained in the feed cone.

5. Jim RuffAntennas & Feeds PDR 2/12/02 5 Feed Cone

6. Jim RuffAntennas & Feeds PDR 2/12/02 6 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

7. Jim RuffAntennas & Feeds PDR 2/12/02 7 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?

8. Jim RuffAntennas & Feeds PDR 2/12/02 8

9. Jim RuffAntennas & Feeds PDR 2/12/02 9 Feed Mounting

10. Jim RuffAntennas & Feeds PDR 2/12/02 10 Feed Mounting

11. Jim RuffAntennas & Feeds PDR 2/12/02 11 Feed Mounting

12. Jim RuffAntennas & Feeds PDR 2/12/02 12 Horn Fabrication Laminated Horns (L, S and C) –Similar to VLBA L-Band horns –Reduce weight and simplify construction –Tooling

13. Jim RuffAntennas & Feeds PDR 2/12/02 13 Laminated Horns

14. Jim RuffAntennas & Feeds PDR 2/12/02 14 Laminated Horns

15. Jim RuffAntennas & Feeds PDR 2/12/02 15 Ring Loaded Horns A Proposal for Ring Loaded Horns –Simplify assembly –Simplify receiver mounting –Improve flange mate-up reliability –Reduce manufacturing cost

16. Jim RuffAntennas & Feeds PDR 2/12/02 16 Ring Loaded Horns