In order to fill the gaps in DTV coverage, KBS Technical Research Institute has researched on DTV on-channel repeating systems as well as DTV translators. The on-channel repeater can reuse frequency resources for expanding service coverage. but it has also many restricts in applications for ATSC DTV system. Thiss Paper compares two kinds of DTV on-channel repealer systems and also presents field test results of both systems. From these results, we Infer their characteristics and summarize the conditions and possibilities of the application for our broadcasting networks.