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CIMA STATUS Rfi update

CIMA STATUS Rfi update. 2009 ALFA Surveys Workshop Phil Perillat. Talk Outline. CIMA status CIMA versions Position errs alfa outer beams in mock data. RFI: Radars, Satellites, intermods. Monitoring available at AO. Online: http://www.naic.edu/~phil/talks/talks.html alfaSurveys09.

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CIMA STATUS Rfi update

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  1. CIMA STATUSRfi update 2009 ALFA Surveys Workshop Phil Perillat ALFA Surveys Workshop: 10-11 december 2009

  2. Talk Outline • CIMA status • CIMA versions • Position errs alfa outer beams in mock data. • RFI: • Radars, Satellites, intermods. • Monitoring available at AO. Online: http://www.naic.edu/~phil/talks/talks.html alfaSurveys09 ALFA Surveys Workshop: 10-11 december 2009

  3. CIMA Versions • Moving to mock single pixel V3.2 • includes functionality of previous versions. • Lets you specify projid for commensal observer’s files. • Requires update of config files for mock parameters. ALFA Surveys Workshop: 10-11 december 2009

  4. CIMA: Running wapps&mock • Scan mode (start,stop many times): • Mocks start 3 secs after wapps and finish 3 secs after wapps. Scan takes 6 secs longer • Continuous mode (start once, leave running) • alfalfa/p2030 • Wapps run scan mode, mocks started once and left running. No impact on wapp running. • Single pixel: • Wapp IF=250/275, Mock IF=325 so can’t be run together (Not so nice for pulsar verification). Will fix this in the future. ALFA Surveys Workshop: 10-11 december 2009

  5. ALFA outer beam position errors in Mock fits files • Problem only in mock fits files: cima and psrfits. • azPos= azCenter + azBmOffGc/sin(za) • azBmOffGc= -azLen0*cos(th) • Th=(beamNum-5)*60 - rotationAngle • Error was: • azPos= azCenter + azBmOffGc*sin(za) • Th=(beamNum-5)*60 + rotationAngle • All positions then back computed from az,za • When problem was fixed: • 1/sinza: 17nov09 cimaV2.01,psrfVer:3.41 • Rotation Error: 01dec09. cimaV2.02, psrfVer:3.42 • See http://www.naic.edu/~phil/modhistory.html -->30nov09 • Will write program to correct positions in files. ALFA Surveys Workshop: 10-11 december 2009

  6. Rfi Known culprits • Radars: (http://www.naic.edu/~phil/rfi/rfi.html) • 1330/1350 faa radar • (1261/1246),(1256,1242) Aerostat balloon • (1270),(1290) remy radar (1 or the other) • (1232,1274,1241,1256) punta salinas modeA ALFA Surveys Workshop: 10-11 december 2009

  7. Global Navigation Satellites • Galileo:(E6 1260-1300) commercial service coded. • Giove-B launched 27apr08 uses E6.(5.115 Mhz) till 18mar09. ALFA Surveys Workshop: 10-11 december 2009

  8. Examples of rfi with alfa/mocks • GPS L2 @ 1227.6 Mhz • Glonass L2 and compass. ALFA Surveys Workshop: 10-11 december 2009

  9. Mock/Wapp 1st Mixer Radar Intermods • Compute intermods first alfa mixer to 10th order • Use 1375 Mhz cfr – galfacts,auds,ages,p2030. • Use 1385 Mhz cfr – alfalfa, p2030 commensal • Examples of intermods: • Auds:1375,1402,1425,1475,1480 birdies. • Complete table of 1st mixer mocks/wapps, 2nd mixer mocks • http://www.naic.edu/~phil/mbeam/problems/rdr_intermods_pdev.html ALFA Surveys Workshop: 10-11 december 2009

  10. Alfa long recovery times • Alfa amps were taking > 30 secs to recover from radar saturation. • sep09 bias adjusted, recovery < 1sec • Oct09 alfa brought to labs, leds installed in amps. In lab this fixed the problem. • Verification of recovery times waiting for final led bias adjustments. ALFA Surveys Workshop: 10-11 december 2009

  11. Rfi Monitoring at AO • location= http://www.naic.edu/~phil • Rfi: fractional occurrence by month (wapp,icorr data) • Using telescope data, compute the fraction of time the rms noise in a channel is 3 sigma > than expected. • Display is a histogram of fractional occurrence vs frequency • Rfi: hilltop monitoring. Plots of previous day. • Uses spectrum analyzer and an omni directional antenna. Tsys is about 1000K, Channel width=3 Mhz, 60 sec peak holds. • /pkg/aosoft/common/bin/imgui to display individual spectra (on AO computers) of any date. • Screen shot of program with data from a2133 data 18apr09 ALFA Surveys Workshop: 10-11 december 2009

  12. Summary • CIMA • Write programs to correct alfa outer beam positions for mock fits files (cimafits and psrfits)., • Commensal observering using 2 mock spectrometers might want to migrate to Version mocksp so they can specify the 2nd project id filename(may not be worth it). • Running mocks and wapps together, mocks start, finish 3 seconds after wapps. • Rfi • GNS satellites at 1220-1270 cause rfi • IDL routines to measure distance from beam. Probably can go a few days into the future and still have reasonable error. • Radar intermods occuring in 1st/2nd mixing stages. • Questions? ALFA Surveys Workshop: 10-11 december 2009

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