If I tune my TV with antenna to no post, it produces noise; about 1% of which comes from microwave background radiation. When I tune my TV to a post, the hiss disappears. Why?
Asker: Eric, 70 years old
Answer
Dear Eric,
If a device is not receiving a signal, the gain is automatically increased to try to receive a weak signal. This makes the noise “visible” as snow. Even with a bad (analogue) signal you will see snow. However, you can no longer make this phenomenon visible with an old device in Belgium, as all broadcasts are now digital.
Kind regards,
Manu Van Lil
Answered by
prof. dr. ir. Emmanuel Van Lil
Telecommunications, radio navigation systems and radar systems
Catholic University of Leuven
Old Market 13 3000 Leuven
https://www.kuleuven.be/
Old Market 13 3000 Leuven
https://www.kuleuven.be/
.