Speakers
Description
Interference arriving from over-the-horizon (OTH) is a known systematic for 21cm cosmology and other MWA science cases, but no predictive model or systematic survey exists. It is most easily seen in TV channels in the 175–200 MHz band. EDGES has logged continuous 24-hr power spectra since 2010, providing a unique long-baseline record of the RFI environment at the MRO. The daily format of the archive is well suited to rapid classification. We visually inspected two years of EDGES data and developed a four-tier classification scheme for OTH propagation channel quality. Any event classified lasted long enough to rule out the better understood short duration effect of airplane/satellite reflections. We have so far classified 2016-2017 finding 16 events and 13 in 2024-2025, out of approximately 300 nights of data in each period. We find a repeatable seasonal trend of events during Austral summer which suggests an atmospheric mechanism. Day-to-day variability within seasons could reflect meteorological modulation. If it does, a model based on weather data could supplement current flagging methods.
| Timeslot preferences | this can be a short one 15-20 minutes is plenty. Put in 21cm session or maybe "observatory" stuff |
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