Am not sure why the system would not display my reply.
Still, as posted....
Still, proposed workaround is to make use of an external ATSC tuner (for use instead of the built-in DVB tuner). The idea is to "...get american tv channels..." and then feed these channels as audio/video signals to the DMR-BWT740. Please click HERE for such external ATSC tuners or set-top-box.
Then depending on the version of the DMR-BWT740, an RCA to SCART adapter may be needed similar to the product shown HERE.