1. ATA Antennas Feeds and Systems NSF Review 8/05/08 Jack Welch

2. The Allen Telescope Array of 350 dishes in Northern CA ~ 2010

3. Array of a Large Number of Small Dishes (LNSD) A Survey Telescope with large field of View For Multiple Pointings, point source sensitivity is proportional to ND, not NDD Single Wide Band Feed insures frequency agility Complementary to other cm wave telescopes US Pathfinder for the SKA mid-band

6. A “Green Telescope” All ambient antenna heating and cooling is done by underground air flow

7. ATA - 350 Dishes Made By TVRO Companies 2.4m secondary 6m primary Log-periodic Feed with Actuator Shroud Radome

8. 6m Antenna Optics Offset Gregorian - Unblocked Aperture Higher Gain Lower sidelobes -15db Shroud lowers spillover and background noise and interference Total surface RMS=.7mm Wide field of View: 3degrees at 1 GHz Aperture efficiency > 0.6

9. The Antenna Pattern At 2.3 GHz

11. Dewar/Cryo 12” Dewar Refrigerator LNAs

14. Wideband Feed (Log Periodic) Range: 0.5 – 11 GHz Input reflection < -15 db LNA within dewar at 62K Cryocooler inside the feed Feed gain 11.5 db +/- 1 db Feed f/D =.65 All receiver electronics a part of the feed Entire analog band sent to lab in fibers Dual linear polarization

15. Overall System Four RF Downconverters produce 600 MHz Dual Polarized Bands at Any Input Frequency Filters feed 100 MHz bands to backends AD Converters (8 bit) drive Spectral Correlators and beamformers Simultaneous SETI and other astronomy Observing Enabled Good Overall gain Stability for Single Antenna Observations of Large Scale Structure