The NEC does not require that the coax for an attic antenna be connected to a grounding block connected to the house electrical system ground, but in cases where there is strong interference from local signals (like FM), it might be a good idea. When the coax is not grounded a strong signal can get directly into the TV cabinet and make any filters less effective.
If the antenna is
outside, the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.
