Two photon fields to date, are generated by a fully coherent pump beam. We have experimentally studied the generation of polarisation entangled single photon pairs using a partially coherent pump beam. The spatial coherence effects of the pump beam on the coincidence detection of an entangled single photon source was investigated. The fully coherent coincidence detection was compared to the partial coherence detection. The results show that the partial coherence of the pump beam leads to an increase in coincidence detection. The coherence properties of a beam is significant for freespace optical transmission specifically for free-space quantum communication over long distances.