assume your on sky mate..you either have a dodgy LNB or your dish needs realigned...as a short term measure try this
press services
then 4 for system setup
then 4 for add channels
then type in:
11585
for the frequency
H
for the polarisation
click down to find channels
press select
move down to "Setanta Sports"
press the yellow button on your remote
then press select
then scroll back to other channels, and select
setanta sports
and you should at least get setanta 1