Probing the Dark Ages at Z~20: The SCI-HI 21 cm All-Sky Spectrum
  Experiment
  We present first results from the SCI-HI experiment, which we used to measure
the all-sky-averaged \cm brightness temperature in the redshift range
14.8<z<22.7. The instrument consists of a single broadband sub-wavelength size
antenna and a sampling system for real-time data processing and recording.
Preliminary observations were completed in June 2013 at Isla Guadalupe, a
Mexican biosphere reserve located in the Pacific Ocean. The data was cleaned to
excise channels contaminated by radio frequency interference (RFI), and the
system response was calibrated by comparing the measured brightness temperature
to the Global Sky Model of the Galaxy and by independent measurement of Johnson
noise from a calibration terminator. We present our results, discuss the
cosmological implications, and describe plans for future work.
