By that I assume you mean the noise when the dish hits "something" solid (a wall, etc.)!
So, all he has to do it to move the dish
gently by a small amount to the E (say from Astra 2 at 28.2E to Eutelsat 33 at 33E) or W (say from Thor at 1W to Eutelsat 8 West B at 8W) of the existing set of sats, and then so on further to the E and to the W - and take a look at the dish after each movement to see if it is getting close to anything solid!
Then set the dish E& W movement limits in the Motor menu (as described
here for example - does not seem to be in the manual, which also true for a lot of other functions/adjustments which exist but are not documented in that book
) to prevent the dish going any further along the arc in those directions.