  We demonstrate that at 1.4 GHz the combined response of sources detected
serendipitously in deep, wide-field VLBI images is sufficient to permit
self-calibration techniques to be employed. This technique of "full-beam" VLBI
self-calibration permits coherent VLBI observations to be successfully
conducted in any random direction on the sky, thereby enabling very faint radio
sources to be detected. Via full-beam self-calibration, Global VLBI
observations can equal and indeed surpass the level of sensitivity achieved by
connected arrays. This technique will enable large-scale VLBI surveys of the
faint radio source population to be conducted, in addition to targeted
observations of faint sources of special interest (e.g. GRBs, SNe, SNR and
low-luminosity AGN).
