By David Katzmaier
(July 20, 2005)

If you have an HDTV with a built-in digital tuner, you can get high-def programming without paying a dime in monthly subscription fees to the local cable or satellite megaconglomerate. You can also enjoy free over-the-air high-def broadcasts if you have an HDTV-ready television connected to an external high-def tuner, such as the Humax HFA100.

All you need, so the story goes, is to connect an antenna. Free high-def programming is explained in depth here, but in short, you can receive high-def broadcasts from the major networks--ABC, NBC, CBS, Fox, and PBS--over the air in most areas of the country today.

Any inexpensive indoor antenna such as the Zenith ZHDTV1 (our current indoor favorite) might do the trick in areas where you're close to the broadcast tower and don't have too much nearby interference, such as tall buildings. In fact, before heading up to the roof, it's worth trying an indoor model to see if you get lucky.

If indoor doesn't work, hit the roof
In most cases, you'll need to install an outdoor antenna to receive all of your local over-the-air stations without dropouts. The best place to do this is the roof of your house or apartment building.

If your landlord or co-op board prohibits the installation of antennas in your building, you still have the right to install one in an "exclusive use" area--for details see the FCC's Over-the-Air Reception Devices Rule. Because HDTV signals are line-of-sight, a higher placement will usually result in better reception and be less subject to interference. There are some differences between installing an HDTV antenna compared to a standard antenna, so we'll walk you through it.

Watch free HDTV with an outdoor antenna

Before you get started with this project, we recommend that you have the following:

Watch free HDTV with an outdoor antenna

There are lots of outdoor HDTV antennas available today, and choosing the right one may seem like an intimidating process. Happily, the Consumer Electronics Association (CEA) has created a Web site that makes deciding on an antenna much easier. It's called Antennaweb.org.

There you'll enter your address and be told which antennas best fit your location, based on relation to the broadcast tower(s) in your area and factors such as the height of your house (single-story or multistory) and whether you have any tall trees or buildings nearby. The resulting list will show you which type of antenna best suits your location. The CEA uses a color-coding system--for example, red designates a "medium directional antenna," which the CEA describes as follows:

"These medium-size, multielement antennas are the most popular rooftop antenna because of their modest size and ghost-reducing characteristics. These are best used if there are any ghost-producing reflective structures near your location."

So you simply purchase a CEA-certified outdoor antenna that qualifies for that color coding. Many antennas qualify for more than one color, and the list that the site generates often has more than one color. If you'd like to receive stations that encompass more than one color, you should buy an antenna that qualifies for those colors. You still may have to make a compromise when aiming the antenna, however, if some of the nearby broadcast towers lie at disparate compass points. Antennaweb has a mapping feature that can greatly assist in aiming your antenna (you'll learn more about how to use this feature in step 5).

If you already have an antenna for analog TV, it never hurts to try hooking it up to your digital TV to see what stations you can grab. Also, many people get perfectly good reception of DTV stations using a standard outdoor antenna as opposed to one that's marketed for HDTV reception.

It's a good idea to get an antenna with a good return policy, in case it doesn't work for you.

Watch free HDTV with an outdoor antenna

WARNING: CNET Networks is not responsible for any injuries or problems that may occur when installing an antenna. Please take proper safety precautions if you decide to install your antenna in any potentially dangerous location.

Check the list of stations from Antennaweb.org and try to find a location on the roof that's free of obstacles between it and the principal broadcast direction. It's a good idea at this point to choose one broadcast tower as the main one and decide to aim your antenna there--splitting the difference between two broadcast towers doesn't work that well for digital signals. If you have two nearby broadcast locations that are equally desirable and more than 30 degrees apart, you could install a device called an antenna rotator, but that's beyond the scope of this project. Alternately, you could mount separate antennas pointed in opposite directions.

Now assemble the rest of the antenna, but mount it only enough to keep it fixed in one location (permanent mounting will come later). You should leave plenty of play so that the antenna is easily adjustable along all of its axes. HDTV antennas are highly sensitive to location and obstacles, so you want to have the option to move the whole assembly if you need to.

Next, attach the coaxial cable and run it down to your television or receiver. Don't affix anything permanently yet, since you may have to move the antenna. You may have to eventually drill through walls for a clean installation, but for now, just run it through the window.

Placement tips

• HDTV antennas are usually designed to point in the direction of one source and reject other sources (multipath). Keep this in mind during placement.
• The behavior of the antenna is affected by nearby large metallic objects. Try to keep a few feet of distance between the antenna and such objects.
• If you live in lower area with a hill or large obstruction between you and the principal broadcast location, you may not be able to receive a signal at all. In this case, you'll have to get cable or satellite for HDTV.
• If you live more than 70 miles from the broadcast tower, you may need to elevate the antenna higher than the house to receive a signal.
  
  

Watch free HDTV with an outdoor antenna

For this step, it really helps to work with a partner near the HDTV itself. Today's HDTVs and digital receivers have signal-strength meters built in, which are designed to help aim an antenna properly. This meter will go up or down drastically depending on the orientation of the antenna, and the goal is to position the antenna in a way that achieves maximum signal strength for as many stations as you want to receive.

Once you have a station locked in, cross-reference the chart and make sure it's coming from the main broadcast location. Then adjust the antenna's angle, height, and other parameters to arrive at a nice strong signal for that location. Sometimes the slightest adjustment can make a major difference in signal strength. Check other channels from that tower--they should come in with a similarly strong signal.

If you're missing major stations and channels, you can try positioning your antenna to split the difference between more than one tower, but again, this may result in too-low signal strength from your main broadcast tower. If you want to address towers that are farther than 30 degrees apart, your best bet is to get an antenna rotator or use more than one antenna.

Tip:
If your reception is still spotty or you're getting only a few stations, you can do a couple of things:

• Try another antenna.
• If you live within five miles of the main tower, the signal may be too strong. Attach an attenuator (10db or 20db) to reduce the signal.
• If the tower is also broadcasting FM, it may interfere with HDTV reception. Attach an FM trap to filter out the unwanted frequencies.
• If the line is being split, combined, or rerouted in any way, use a direct line from antenna to box.

Watch free HDTV with an outdoor antenna

WARNING: Proceed at your own risk and discretion. Please take proper safety precautions if you decide to install your antenna on the roof or another potentially dangerous location. CNET recommends consulting a professional for help installing a rooftop antenna. CNET is not responsible for any injuries or problems that may occur when installing an antenna.

Once you've oriented the antenna for best reception, tighten the screws and secure the rest of the antenna assembly. Then secure the coaxial cable run into your house, avoiding crossing other cables or power lines. We recommend you seal the outdoor leads (where the cable screws onto the antenna) with something called coax seal or RTV to avoid corrosion.

Important: Grounding
At this point you must ground the antenna to protect your valuable HDTV equipment from electrical surges. First, make sure all of your gear is plugged into a quality surge protector, preferably one that's guaranteed for at least the amount of your equipment cost.

Then attach a coax grounding block, available at any RadioShack, to a point near where the cable enters the building. Connect one length of your coax antenna cable between the block and antenna and a second length between the other end of the block and your HDTV receiver. Then run a length of grounding wire from the block to a suitable grounding point.

Grounding points can be a true earth ground (defined as a length of pipe driven eight feet or more into the ground) or a cold-water pipe. The best place to find true ground is at an electrical sub-panel, comms wiring closet or the building construction steel itself. If you use a pipe, make sure to remove any paint at the point to which you attach the grounding wire. Since in new construction many pipes are PVC along some of their lenghts instead of metal, they may not be reliable grounds.

You also need to ground the antenna itself by running another length of grounding wire between the antenna and ground point. Your antenna itself may have special instructions for grounding; if so, be sure to follow them. If you're not sure you've grounded your antenna correctly, consult a professional experienced in installing antennas or the manufacturer of your antenna itself.

With your antenna safely installed, you can now enjoy free over-the-air HDTV.