Observed brightness temperature from bremsstrahlung emission by star‐forming clouds at z > 10 and ionized regions of the smooth IGM in our standard model. The emission from the star‐forming clouds exists only if the clouds retain their gas over the lifetime of their stellar population. For comparison, we show the bremsstrahlung emission from the Lyα forest between 0 < z < 5 for a UV background of 10⁻²¹ ergs cm⁻² s⁻¹ Hz⁻¹ sr⁻¹ at the Lyman limit (Loeb 1996). We also show the CMB spectrum and the proposed sensitivity of the DIMES experiment (Kogut 1996; see also http://ceylon.gsfc.nasa.gov/DIMES).