Several users have reported problems tuning channels in RC3 with DVB-T cards.

Forum links include

http://forum.team-mediaportal.com/mediaportal-1-1-0-rc-3-519/no-tv-signal-82441/
http://forum.team-mediaportal.com/mediaportal-1-1-0-rc-3-519/dvb-t-stops-working-82467/
http://forum.team-mediaportal.com/mediaportal-1-1-0-rc-3-519/hauppauge-hvr-1300-gives-could-not-lock-signal-82461/

It would appear that these problems are a result of fixing

http://mantis.team-mediaportal.com/view.php?id=2880

A binary has been tested internally and confirmed by two users to fix this problem.

h4. Additional Information
Internal forum thread

http://forum.team-mediaportal.com/mediaportal-releases-315/users-having-tuning-issues-rc3-82526/