How does a TV aerial work?

Wednesday 22nd July 2009
Submitted by Gareth Mitchell
Brian Newlove, Cottingham

Like any antenna, a TV aerial is made of metal. Electromagnetic waves carrying television signals induce tiny electrical currents in the antenna. The television set amplifies the signal and selects the information that carries vision and sound. Engineers refer to TV aerials as 'yagi arrays'. The metal plate at the array's far end reflects the signal back down its length. The parallel rod-like structures that run along the length of the aerial are specially spaced to optimise signal strength.

Why does a windscreen crack in a zig-zag?
previous qanda Article
Why can't I recycle takeaway pizza cartons?
next qanda Article
Q&A Tabs

No. At least, not in the popular sense that creative people are more ‘right-brained’ than logical or analytical people are: a study that scanned the brains of over 1,000 people found...

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Trees release oxygen when they use energy from sunlight to make glucose from carbon dioxide and water. Like all plants, trees also use oxygen when they split glucose back down to release energy to...

Chewing gum has been with us since the Stone Age - chicle gum was made from the sap of the Sapodilla tree. Most modern gums are based on a synthetic equivalent, a rubbery material called...

In DAB, the transmission equipment samples the signal in chunks, so it takes a few fractions of a second to convert it into binary. When the signal arrives at your DAB receiver, it streams the...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here