  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.
