Radio-Frequency Interference at the McGill Arctic Research Station

TL;DR

This study identifies the McGill Arctic Research Station as a notably RFI-quiet site suitable for radio observations, with low interference levels of around 1.8% in the 20-125 MHz range, even during active summer conditions.

Contribution

It reports the first RFI occupancy measurements at MARS, demonstrating its suitability for sensitive radio astronomy observations.

Findings

RFI occupancy at MARS is approximately 1.8% in 20-125 MHz.

The FM band (88-108 MHz) has RFI occupancy of at most 1.6%.

Measurements represent the maximum RFI environment during summer conditions.

Abstract

The frequencies of interest for redshifted 21 cm observations are heavily affected by terrestrial radio-frequency interference (RFI). We identify the McGill Arctic Research Station (MARS) as a new RFI-quiet site and report its RFI occupancy using 122 hours of data taken with a prototype antenna station developed for the Array of Long-Baseline Antennas for Taking Radio Observations from the Sub-Antarctic. Using an RFI flagging process tailored to the MARS data, we find an overall RFI occupancy of 1.8% averaged over 20-125 MHz. In particular, the FM broadcast band (88-108 MHz) is found to have an RFI occupancy of at most 1.6%. The data were taken during the Arctic summer, when degraded ionospheric conditions and an active research base contributed to increased RFI. The results quoted here therefore represent the maximum-level RFI environment at MARS.