http://www.linuxtv.org/vdrwiki/index.php/Femon-plugin

DVB Frontend Status Monitor is a VDR plugin that displays some signal
information parameters of the current tuned channel on OSD. You can zap
through all your channels and the plugin should be monitoring always the
right frontend. The transponder and stream information are also available
in advanced display modes.

WWW: http://www.saunalahti.fi/~rahrenbe/vdr/femon/