  We estimate the signal from large scale structure at high redshifts in
redshifted 21cm line. We focus on z ~ 3 and the LCDM cosmology. We assume that
neutral hydrogen is to be found only in galaxies, and normalise the total
content to the density parameter of neutral hydrogen in damped Lyman alpha
absorption systems (DLAS). We find that the rms fluctuations due to the large
scale distribution of galaxies is very small and cannot be observed at angular
scales probed by present day telescopes. We have used the sensitivity of the
Giant meter-wave Radio Telescope (GMRT) for comparison. We find that
observations stretching over 1000hours will be required for a 3 sigma detection
of such objects.
