I receive only a jerky picture of the Smart Baby Monitor. Why is that?

There are various sources that can interfere with the transmission of the image:
Microwaves: Microwaves near the Smart Baby Monitor can interfere with the wireless connection to the baby monitor.
Phones, audio and video devices on 2.4 GHz base: These devices can also interfere with the wireless connection.
Walls: reinforced concrete of more than 15cm, can lead to noticeable interference of the wireless connection.