Signal VI: Dark Ages: Baryon Oscillations Very low frequency (<75MHz) = Long Wavelength Array Very difficult to detect  Signal: 10 arcmin, 10mk => S 30MHz = 0.02 mJy  SKA sens in 1000hrs: = 20000K at 50MHz => rms = 0.2 mJy  Need > 10 SKAs  Need DNR > 1e6 z=50 z=150 Barkana & Loeb 2005