Why doesn't white noise appear on TVs anymore?

White noise is a common problem with 20th century TV models .

Snowy white screens were a staple of the 20th century TV experience, but now they're a thing of the past. Why aren't TVs grainy anymore?

Only available on older TV models

White noise is common on older TVs.

White noise is a common problem on older TVs . It appears when we tune the TV to an unavailable channel.

To understand why older TVs have such noise, you have to understand how analog TVs work. In simple terms, older TVs work like radios, but with a picture added.

Like radio, you can hear clear and crisp sound when sitting at home or in the city, but it is full of noise or distortion when walking through the woods or in deserted areas where radio waves are limited. Analog TV signals also fluctuate from very strong to almost undetectable.

And, just like an old radio, when you tune your analog TV to a channel that isn't used in your area, the TV is still trying to pull the signal but can't find the appropriate TV program.

When no signal is detected, the TV will 'play' a background image with randomly changing noise instead of a picture. The noise on older analog TVs is a combination of electrical noise in the TV itself , radio frequencies from the local environment, and radiation from space. In fact, some of the noise on older TVs is gamma radiation from the Big Bang over billions of years and the expansion of the universe, which turns into microwave radiation. A small amount of the radiation hits the Earth, passes through our atmosphere, and appears as noise on analog TVs.

Why modern TVs don't have white noise

When there is no image signal, modern TVs today only display a blank screen or sometimes have some additional information to guide the user (Photo: How To Geek)

To understand why modern TVs no longer have white noise, we need to go back and look at the history of how television broadcasting has changed on 21st century TV models.

In 1996, the United States Congress passed the Telecommunications Act, which included the transition from analog to digital television, freeing up a range of radio frequencies for other purposes, including mobile communications and emergency services.

Although the end of analog television broadcasting date was delayed several times from the original date specified in the Telecommunications Act of 1996, by June 12, 2009, all high-power analog stations in the United States had switched to digital signals.

Because of that change, modern TVs do not have analogue tuners. When you tune a modern TV with a digital tuner to an unavailable channel, the TV screen will show nothing but a blank screen with a 'No Signal' message and no noise whatsoever.

That's because digital TV signals are binary . Either the antenna receives the signal and produces a picture or it doesn't, there's no noise or any of the other relics of analog TV.

When there is no video signal, modern TVs today simply display a blank screen or sometimes some additional information to guide the user.