When installing a loft TV or radio aerial, always be careful where you step inside your loft, especially if it isn't boarded. If your loft is un-boarded, you must only step and place heavy items like TV's on the wooden rafters, or the ceiling plasterboard will be damaged. Plasterboard will not withstand the weight of a person and repairing ceiling damage can be very expensive.
When fitting a TV aerial into a loft, never disturb or tread on existing power cables or pipe work. Avoid disturbing any fibreglass insulation as much as possible. It is sensible to wear insulated sole shoes and a facemask to protect against breathing in fibreglass dust.