Radio Astronomy Spectrum Management in practice – Australia (ATNF) Tasso Tzioumis Australia Telescope National Facility 10 June 2002
Tasso Tzioumis Greenback Overview Radio telescopes in Australia RFI characterisation Measured spectra Computed spectra INTER Projects SKA radio-quiet reserve 3/12/2018 Tasso Tzioumis Greenback
Radio Telescopes in Australia 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback ATCA RFI measurements April 1995, ATCA short baselines 20, 13, 5, 3 cm bands April 1997, 13 cm band 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback 20cm band April 1995 13cm band April 1995 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback 6cm band April 1995 3cm band April 1995 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback 13cm band April 1997 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback 13cm band April 1995 13cm band April 1997 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback RFI Characterisation Predictions from ACA Database John Sarkissian, Parkes RF plots at each band, Integrated flux, RFI at each Oz telescope Includes satellite services where known 2nd and 3rd harmonics can be shown Interactive Interference Characterisation (INTER) www.parkes.atnf.csiro.au 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback Integrated Flux 0.1-10 GHz 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback RF Flux Distribution 3/12/2018 Tasso Tzioumis Greenback
RF Transmitters near Parkes 3/12/2018 Tasso Tzioumis Greenback
RFI monitoring and Mitigation Parkes program (Mal Smith) Identify internal interference Screen observatory equipment Interference Monitoring System (IMS) Radiometer system sampler/correlator lower noise floor -234.7 dBW/m^2/Hz 3/12/2018 Tasso Tzioumis Greenback
Terrestrial Interference Forte satellite: 131MHz 3/12/2018 Tasso Tzioumis Greenback FORTÉ satellite: 131 MHz
Possible SKA configuration 3/12/2018 Tasso Tzioumis Greenback
SKA location Radio Quiet Reserve 3/12/2018 Tasso Tzioumis Greenback
Square-Kilometre Array Australia Luneburg Lens All sky coverage multiple simultaneous beams Possible design 5-m spheres Each patch 100 m diameter 100s of patches 3/12/2018 Tasso Tzioumis Greenback
SKA Location WA Radio Quiet Reserve RFI measurement system Funded by WA state government First results march-April 2001 30-150 MHz 1060-1800 MHz Site comparison 2002 Noise floor > 30db ITU IMS under construction 3/12/2018 Tasso Tzioumis Greenback
RFI measurement equipment Antenna LNA SpecAn RBW = 3kHz (100Hz) Determines band • Sensitivity determined by external noise Maximum gain used • Gain ~ 40 dB 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback IMS Modified Multibeam sampler/correlator 1024 or 2048 channel autocorrelation Sampler: 2-bit, 3-level,128Msamp/sec, IF bandwidth 64 MHz Under testing Sensitivity: For G=8dBi, at 1400 MHz, Tsys=440K, 1024ch, 64 MHz BW, 5s integ., average 100 -234.7 dBW/m^2/Hz 3/12/2018 Tasso Tzioumis Greenback
Tasso Tzioumis Greenback Summary RFI characterisation at Australian telescopes Measured spectra Computed spectra – ACA database INTER – interactive characterisation Projects – monitoring and mitigation SKA radio-quiet reserve 3/12/2018 Tasso Tzioumis Greenback