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

At the manufacturing stage, when juice from oranges has been extracted and the pulp removed, the product is processed into two forms: not-from-concentrate (NFC) or bulk frozen concentrated orange...

We do, although you'd barely notice. There are two effects, both due to the spin of the Earth. 'Centrifugal force' due to the spinning lowers your body weight by about 0.4 per cent at the equator...

Head hair doesn’t change colour all at once, but many men have grey hair when their eyebrows are still dark. All kinds of body hairs change colour when ageing hair follicles stop producing...

It’s long been known that just over-heating, let alone burning, some foods can lead to the formation of compounds linked to cancer. These include heterocyclic amines and so-called polycyclic...

Both fats and oils are molecules shaped like a capital E with a glycerol spine and arms made of fatty acid chains. In animals, the carbon atoms in the fatty acids are saturated with hydrogen atoms...

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