What you need to get HD

You can get free off-air broadcast HD if you have a UHF/VHF antenna and an HDTV with a digital ATSC tuner (all new TVs have one) or an HD-ready TV used with an HD-capable digital converter box (not a basic, coupon-eligible model). You connect the antenna to the TV or the box with the RF cable, which can carry HD. You must be near a TV station transmitting digital signals, and the fewer obstructions from trees and buildings, the better.

Most consumers pay for a high-definition TV from cable, satellite, or a phone company. To get high-def content from a service provider, you need:

HD service

Digital programming can be either standard- or high-definition, so you must specify that you want high-def.

An HD-capable receiver

You can lease or buy one from the provider. Check the manual to be sure the receiver is properly set to output HD resolution. If you have a TV that’s CableCard-compatible, you can use a card (rented from the company) instead of a receiver. In addition, if your TV contains a QAM tuner, you might be able to get some high-def cable stations without using a set-top box by plugging a cable directly into your TV’s RF input and scanning for digital cable channels. Check with your provider to see what your options are.

Component-video or HDMI cables

You need these to carry high-def from the receiver to the TV; other cables, such as S-video, can't carry high-def. You don't need expensive cables; any decently constructed cables are fine for typical use.

An HD channel

The HD version of a channel has a different number from its standard-definition counterpart and usually has the letters HD in the onscreen program guide listing. You'll notice some variation in picture quality on different HD channels and even among programs on the same station. That's because even HD channels sometimes show standard-definition programs (usually indicated by dark bars on the sides of the images). Also, the quality of HD signals being fed to the TV varies, depending on whether a program originated as HD or was converted from a lower resolution and how much the signal was compressed in transmission. Even the best set can't display top quality from a mediocre signal, so don't blame the TV. Reruns of standard-definition TV shows and VHS videos can actually look worse than on your analog set because a big-screen HDTV can reveal the flaws in a poor signal.