Why do the pictures obtained on T.V. shake when an aeroplane pass from above
at a low hight ?
Answers
in the modern days,we use wireless network systems vastly in our daily lifestyle.
Modern television broadcasting system also works on the wireless network system,in a frequency range of 50MHz to 850MHz.
Aeroplane network system works in 123MHz which interferes into the TV networks.
That's why TV pictures shake while an aeroplane passing in a low height,due to the frequency range interference.
Since the aircraft is moving, this interference pattern thus produced is unstable, which results in the shaking if the TV image.
When you are watching TV using an antenna you are seeing a signal coming directly from the TV station’s tower. When a aircraft flies over, some of this TV signal is reflected off it and is also picked up by your antenna. Because this signal is traveling a longer path it will arrive in phase (increasing) or out of phase (reducing) the direct signal. Since the aircraft is moving this will be constantly changing in and out of phase thus causing the “fluttering” effect on the signal