NATIONAL ASTRONOMY AND IONOSPHERE CENTER RFI in the

NATIONAL ASTRONOMY AND IONOSPHERE CENTER RFI in the alpha band pass Murray Lewis Senior Research Associate Radio Astronomy Group

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Propose to cover FCC frequency allocations in spectral region GPS Galileo PR Radars in band RFI Mitigation possibilities radar blankers! nine level sampling! algorithms! cross correlation between feeds Reinforcement of AO anti-RFI activity!

NATIONAL ASTRONOMY AND IONOSPHERE CENTER The frequency range covered by alpha is from 1225 to 1525 MHz

NATIONAL ASTRONOMY AND IONOSPHERE CENTER

NATIONAL ASTRONOMY AND IONOSPHERE CENTER

NATIONAL ASTRONOMY AND IONOSPHERE CENTER GPS L 1, L 2, L 5 General coverage -158 d. BW Spot Beam -138 d. BW L 2 L 1 Alpha 1225 - 1525

NATIONAL ASTRONOMY AND IONOSPHERE CENTER GPS L 1 & L 2 -157 d. BW for C/A -160 d. BW for Y L 5 -154 d. BW ≈24 MHz, full time occupancy This is 6 d. B stronger than present L 1 & L 2 L 5 spfd ~-205 d. BW/m^2/Hz 1164 -1188 MHz ~-197 d. BW/m^2/Hz in center 5 - 8 satellites always available Also, of concern, GPS L 3 circa 1381 MHz

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Galileo -- full set due 2008 E 5 A_E 5 B 1164 -1215 MHz E 6 1260 -1300 MHz E 2, L 1, E 1 1559 -1591 MHz (WRC 2000) Use of C_band under consideration To have 30 satellites, in 3 planes, inclination 56 deg 14 hr orbits, radius 23616 km Power 50 W amplifiers peak power 120 W

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Galileo On orbit validation 2001 -5 Deployment 2006 -7 Commercial Ops. 2008 2/4 satellites 26 -28 sats Concern is their presence at 1260 -1300 MHz

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Details of Common/Unusual RFI Available on AO Web Page

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Hilltop Monitor 1200 -1450 MHz

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Blanking San Juan Airport Radars? Examples Surroundings of 1400 -1427 MHz band US has proposed a satellite system Uplink circa 1400, downlink circa 1427 MHz Timing explorer in Space Lab was at 1427 MHz L 3 (GPS) at 1381 MHz

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Fractional occupation of 0. 1 MHz bins

NATIONAL ASTRONOMY AND IONOSPHERE CENTER

400 0 0 500 1000 RATAN-500 1500 2000 1116+28 20 0 0 500 1000 1500 2000

NATIONAL ASTRONOMY AND IONOSPHERE CENTER Arecibo anti-RFI activity importance of L_band to alpha Do you want radar blankers How bothersome is the 1350 MHz birdie? Should you be using 9 -level sampling? Algorithm development