Samsung PN51E6500EFXZA - Manual (Page 52)

If the reception is clear, you do not
have to fine tune the channel, as this is
done automatically during the search
and store operation. If the signal is
weak or distorted, fine tune the channel
manually. Scroll to the left or right until
the image is clear.
N Select the channel, and then select
Fine Tune .
N Fine tuned channels that have been
saved are marked with an asterisk “*”