1. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 1 Antennas and Feeds

2. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 2 Scope Overview Feed Cone Mechanics Feed Manufacturing Electromagnetic Issues Feed Testing Plan

3. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 3 Overview Antennas 28 Antennas Shaped Cassegrain Geometry Existing Optics 1 to 50 GHz Continuous

4. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 4 Overview Feeds Eight Bands L S C X Ku K Ka Q

5. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 5 Overview Feed Cone Optimize G/Tsys No shadowing by adjacent feeds Minimize effects of reflections from adjacent feeds Minimize effects of gravitational sag Effective use of WVR at short wavelengths L S C X Ku K Q Ka

6. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 6 Feed Cone Mechanics Mounting L-Band No shadowing No structural changes outside designated feed cone Additional support View: Looking up from Vertex Room

7. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 7 Feed Cone Mechanics Feed Cone Structure Continuous conductive skin to reduce RFI/EMI Monolithic construction uses honeycomb panels with polycarbonate (thermal advantage) FE analysis complete

8. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 8 Feed Cone Mechanics Feed Mounting/Pointing Provides accurate pointing Improved access and simplified receiver installation and removal

9. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 9 Feed Cone Mechanics Feed Mounting/Pointing

10. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 10 Feed Manufacturing L, S, and C Band feeds use Laminated technique for weight to strength advantages X thru Q Band feeds turned from solid aluminum

11. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 11 Feed Manufacturing Laminated Horns C-Band Aperture Section

12. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 12 Feed Manufacturing Laminated Horns C-Band – Throat Section

13. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 13 Feed Manufacturing Laminated Horns C-Band Bands

14. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 14 Feed Manufacturing Laminated Horns Ring Manufacturing Machine

15. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 15 Feed Manufacturing Ring Loaded Section K-Band Horn w/ Prototype Ring Loaded Section

16. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 16 Electromagnetic Issues Laminated Feed Bands –Welded Solid band Welded and ground –Spiral Band 10-15 thousandths thick w/ conductive bound –Concern Leakage, discontinuities for circumferential currents –Build Prototype?

17. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 17 Electromagnetic Issues Adjacent Feed Interaction –Tasked at PDR (German Cortes, Bruce Veidt) –Near-field evaluation using Gaussian Beam propagation technique (Tuovinen, & Olver) –Evaluated using worst-case parameters and assumptions –Loss in illumination taper efficiency ~0.02% for C→S band case where 2% energy impinges on S-band cylinder

18. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 18 Feed Testing Plan Prototype –Green Bank Facilities –SWR –Beam Patterns (co/cross) –Phase Center [f(ν)] –RF Leakage –Adjacent feed interaction Production –Primary Test SWR (Socorro) Additional Testing as required –Sampling and Archive Patterns for every 6 th feed Full test matrix as required –Monitor process variation and personnel turnover

19. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 19 Prototype Schedule

20. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 20 Production Schedule

21. E. Szpindor, J. Ruff Advisory Committee Briefing June 10-11, 2002 21 Projected Costs (unit cost per band)