Galvanic Separators
Ground breaker or galvanic separator separates ground of antenna and receiver. Without a ground breaker there might be a potential difference between grounding points. This makes ground currents flow in your AV system. You might encounter hum in audio and video. Audio hum you can hear from your speakers. Video hum could cause faint lines rising through your video image. All of this is fixed if you separate all grounds from each other with a ground breaker. This doesn't prevent antenna signal.
