Basics of Installing HDTV Antennas

With the transition from analog to digital television on the horizon (February 17, 2009), many consumers will be forced to upgrade their television systems.

For consumers not interested in an expensive HD programming package, rooftop antennas provide a viable alternative -- digital TV, which includes HD.

Which HDTV antenna should be installed?

In order to pick the right antenna, you need to know the distance and locations of the transmitting towers. If the towers are scattered in your location, an antenna with a wide beam width will be needed.

Getting the antenna with the appropriate gain will also be helpful. It's usually not a good idea to buy more signal strength than necessary.

Too strong of an antenna installed in the shadows of the transmitting towers runs the risk of over-driving the tuner or encouraging multipath interference.

Click here for to determine tower locations, transmitter power and distance from a given address.

How easy is this to retrofit in a house?

Due to their more flexible aiming characteristics, installing an over-the-air (OTA) antenna is generally regarded as easier than most dish installs.

It's as easy as running the coax cable from the antenna to the digital tuner.

Should they be installed indoors or outdoors?

The success rate for an outdoor installation will always be higher, although a significant percentage of installations involve mounting the antenna in the attic.

Depending on roofing materials, signal losses can be as high as 40 percent (or as low as 5 percent) with an attic mount. For most suburban installations, this shouldn't be a problem.

But if you are on the fringe of reception, you may need to consider the necessity of outdoor installation.

What is the minimum cable gauge?

The minimum cable gauge needed for an antenna would be RG59 for short runs, but RG6 coax is preferred.

How long does it take to install?

Most single-tuner installations are finished in less than 20 minutes. However, installations involving extensive signal distribution could take much longer.

What is the height requirement for antenna installations?

The majority of DTV (digital television) signals will be line of sight. So, the higher the antenna, the better chances for success.

Generally, installations where the antenna is mounted at least 20 feet above the surrounding terrain can expect more than 50 miles of range.

Geography will play a big part in how high you will need to mount the antenna. Some valley dwellers may need to invest in long masts to get enough elevation.

What additional equipment or accessories are needed?

Most tools, cables and connectors used for satellite or cable installations would be the same for an over-the-air (OTA) antenna install.

You can often use the "J" mounts for the DBS (direct broadcasting satellite) dishes to mount an OTA antenna.

The only thing unique would be a portable signal meter capable of over-the-air DTV measurements. Most satellite field meters lack this capability.

When is an amplifier needed?

It is important to note that amplifiers cannot create a signal that doesn't exist in the first place, and an amplifier cannot make a poor antenna into a good one.

Be cautious about using amplifiers when the customer is less than 5 miles away from the transmitting towers because the amplifier could possibly overload or exacerbate a multipath condition.

There are certain circumstances, however, in which amps are essential, particularly with cable lengths of more than 100 feet (where as much as one-third of the signal can be lost if an amplifier is not used).

Splitters and diplexers will also result in signal loss. When choosing an amplifier, focus on low noise and overload resistance more than just gain alone.