17

Feb

2009

Getting High-Definition TV Over the Air (OTA)

Over half the people in the United States can receive HDTV broadcasts for free, though many may not know it (or what it is). This is intended to be an easy how-to on getting HDTV broadcasts.

What is High-Definition?

Maybe you’ve heard of HDTV, but aren’t sure what it is. Maybe you bought what you were told was an HDTV, but the cable picture isn’t so clear. There’s a fair amount of confusion here, so a quick explaintion is in order.

Fist off, let’s discuss what it isn’t. HDTV is not just a type of TV set. Most big-screen (and some not-so-big screen) TV sets that are billed as HDTV are actually just "HDTV-capable". This means that they can display high-definition but don’t have any way of receiving the signal. But its a good start, because you’ll need one to get true high-definition.

"Digital cable" isn’t high-definition.. Not even close. Digital cable, at best, has a picture as good than regular (analog) cable. In some cases, its worse than analog cable. It is only "digital" in that it uses digital compression so they can transmit several channels in the same bandwidth as one analog channel. This compression isn’t lossless, so some of the signal will be lost in the process. The reduced quality will look different – it’ll show up as artifacts.

HDTV is a revolution in clarity; its the biggest thing to happen to television since color. You are probably familiar with DVDs – a DVD is quite clear, but it is actually not "high-definition". HDTV provides three or more times the clarity of DVDs, and ten times that of traditional TV. Colors are brighter and edges are sharper. In some cases, it’ll be as clear as looking out the window. See Feldon Central’s website for some examples. The picture is widescreen, so you don’t have to do odd things to make it fit on your widescreen TV. The sound is also CD-quality – you usually hook it to your audio receiver with a fiber or coaxial cable.

Step 1: Reality Check

An antenna may feel like a step back into the 60’s; but this isn’t your dad’s over-the-air TV. This is truely digital, which has several technical advantages over the old analog stuff. Its digital TV (DTV). Its a little harder to receive than the old analog TV, and we’ll discuss that a good bit here.

What you get: Most of the primetime programs on the broadcast channels are high-definition. You can use titantv.com to get an idea of what you’d be able to receive in high definition (HD). Some programs (particularly outside of prime-time) will be standard definition, but still broadcast on the HD channel. They won’t look as good as HD, but they’ll certainly look better than cable or standard broadcast TV. It’s generally not widescreen, so your provider (or your receiver) will put black bars on the sides when those SDTV shows are playing.

The ATSC broadcast standard (the one used to broadcast HD) also has a multicast feature where a station can send out multiple "sub-channels". Most channels multicast an HD signal on the first sub-channel, and a separate signal on the second sub-channel which isn’t actually HD. This is called standard-definition TV (sometimes called "SDTV"). It’s still digital, so it has better clarity and color than a non-digital broadcast. This isn’t always the same signal as the main channel – it might be weather or some other content.

One final note of what you might get – if you watch a lot of standard definition shows (with the black bars on the sides), your TV can "burn in", and the bars can be permanently visible. This is a problem with rear-projection or plasma TVs, but not LCD or DLP. You have to decide for yourself how much you want to watch with these on the screen – a safe amount is probably somewhere between 15% and 50%, but it depends a lot on the TV and the brightness/color settings.

Step 2: Decide when to take the plunge

Before you do anything, you should check to see what sort of HDTV you can get. If you’re in a big city, it could be a lot. If you’re way out in the country, it could be very little. Check antennaweb.org, and see what can be received from your house before you do anything. There is also satellite programming as well (if you have Dish Networks or DirecTV). More programming information is available at AVS Forum.

Another consideration is what you watch. Check titantv.com to see if you like the shows that are in HD. While you’ll get some improvement from the other DTV programs, it won’t be nearly as significant as HD.

Prices on HDTV have come way down over the last couple of years, but its still not cheap. Other than the price of a big-screen TV, which can be $1500 and up, you’ll need to buy a tuner (which starts at around $300). If you have Dish Networks or DirecTV, you’ll want a receiver that can pick up HDTV (they also provide many HD channels via satellite) over the air.
You just have to decide for yourself if its worth the cost. If you already have the HDTV-compatible TV, its just the cost of the tuner. My personal thinking was, I spent all that money on a TV, why not spend a bit more to make it look good?!?!

A final consideration, one which can be a great cause for worry, dwelling, and vexation, is whether you’ll actually be able to receive the signal. Take a look at the antenna section below. You’ll never really know until you try.

Step 3: Get a tuner

If your TV has a built-in HDTV tuner, all you need to do is hook up an antenna. This is becoming more common. Otherwise, you just have a ton of connectors on the back. We’ve discussed tuners, which pick up HDTV, and satellite HD receivers, which can pick up HDTV channels both over-the-air (OTA) and via satellite.

Actually finding an HDTV tuner or receiver can sometimes be difficult. Electronics resellers don’t generally keep very many in stock, and the employees, never seeing them on the shelves, are often completely oblivious abouts HDTV. Several on-line resellers do keep them in stock.
More information on tuner/receiver hardware is available at AVS Forum.

You’ll also need some cables to hook it up. At a minimium, you’ll need a component video cable and an audio cable. The component video cable will have three RCA jacks. If you’re hooking it up to a non-HD TV, you’ll use an s-video cable instead of a component cable. The audio cable will have two RCA jacks – this will get the audio to your TV. If you have a mid- to higher-end audio home theater receiver, you’ll want a fiber or coaxial cable to connect it. If you don’t have any such connector on your audio receiver but you still want to use it for your audio, you may have to decide whether to hook the RCA jacks to your TV or to your audio system. There may be another alternative – you may be able to run the audio through the TV to the audio receiver (you’ll need to see what you have on your TV). This is the sort of thing the salespeople at the electronics store can help with. You don’t have to get the best cables; moderately-priced cables will work quite well.

Step 4: Install an antenna

Other than deciding to spend the money, this is, usually, "the hard part". Picking the right antenna and placing it well is necessary to get a good signal. This section may make it look harrowing, but in reality only part of it will apply to you (depending on your location in relation to the towers from which the stations broadcasts).

First, a couple of general concepts about antennas. The antenna you’ll need for HDTV isn’t anything new or different – just a typical UHF or VHF/UHF antenna. Some antennas are sold as "digital" antennas, but they’re usually just UHF antennas. Most DTV channels are UHF, so you’re usually (but not always) needing a UHF antenna anyway. A major difference between UHF antennas are how directional they are – a highly directional antenna will primarily pick up a signal within a range of a few degrees angle from your house. A directional antenna will generally do a better job of picking up a signal from a given direction than a multi-directional antenna, and will decrease the chances of multipath problems. If you have some VHF (and some UHF) channels, you’ll need a UHF/VHF antenna. The antenna will hook to the TV with a coax cable – an RG-6 cable will provide the best signal, and is preferable for longer runs. New cable is always best – older cable can significantly reduce a UHF signal.

Its difficult to predict how good a signal you’ll get, but there is some pre-work that will help. First off, go to antennaweb.org and find out what direction the station towers are from your house, and whether they use UHF or VHF (channel 13 or under is VHF). Only concern yourself with the DT channels if you’re not trying to get analog broadcasts. Weed out the channels you’re not interested in – this will reduce the directions you now to be concerned about. Now, take a look outside to see if there are major topological obstacles (including hills and skyscrapers) between you and the towers (a compass can be handy at this point!). These obstacles can greatly impact your reception. Terrain and trees are a huge factor. Once you know where the signals are coming from, try to drive around and get a feel for whether or not you’re able to see the towers, line of sight. UHF does not bend over hills. Trees are like sponges and soak up signals, as well as reflecting them, depending on type and whether wet or dry. Note: getting analog stations well isn’t much of a predictor, since they’re different channels and often different bands (VHF vs UHF).

Reflection is a problem with directional signals. It can cause signals to dropout or transmit on multiple paths (confusing receivers). This multipath interference was a big problem with early-generation receivers, but newer receivers are better at dealing with it. Cars and trucks can be particularly bad, since they not only reflect but also move constantly – you don’t want your antenna pointed at a street!

If you’re within 5-10 miles of the tower and there are no major obstacles, you can probably just use a good indoor antenna. The Silver Sensor (made by Antiference in the UK, but sold by Zenith and Gemini) is a very good directional antenna. Just hook it up with a regular TV cable, sold at any discount or electronic store. Placement can be very important – just moving it a few feet can make the difference between a great signal and no signal whatsoever. I got the best signal by pointing it out a sliding glass door toward the antenna. You’ll want to place a directional antenna to point toward the tower. Just try different spots and check the signal on your tuner.

A common thing I hear people say is "I’ll just try a good old rabbit-ear antenna". Those are the remnant of a day when nearly everything was VHF, but most cities have no high-def channels broadcasting on VHF. A looped wire coat-hanger will likely provide a better signal than rabbit-ears. So please, no rabbit-ears!

If you’re within 20 miles, you may be thinking about attic installation. Attic installation is also very popular, but its certainly not guaranteed success. Some attics (particularly newer houses in warm climates) have reflective roof material that will completely block the signal. The roof will degrade the signal in any case – but if you’re close enough to the towers it might not matter. You can try it before you drill holes in the wall – just buy a reasonably long RG-6 cable (try to keep it no more than 50 feet) and run it through the entrance you use to get into the attic. If it works, do a more permanent installation. The attic will at least get the antenna up higher than it might be indoors, and higher is better. A bigger antenna will increase your chances of good reception – but take into consideration the size of your entrance!

20 miles or more from the towers, you’ll probably need an outdoor antenna. Outdoors will give you the best reception (by far). The biggest stumbling block can be homeowners association (HOA). Many HOAs don’t allow outdoor antennas, even though it isn’t generally legal for them to do so. The FCC has mandated that the HOAs can’t do this unless they have exclusive ownership of your roof (see this FCC fact sheet). You may be able to avoid some of this confrontation by installing the antenna inconspicuously. A multi-bowtie antenna can be installed right within a few inches of the wall, if its in the right direction to pick up the signals – the Channelmaster 4221 has been received good reviews, but there are many others. The Silver Sensor could be mounted under an eaves. Be careful to ground the antenna if its mounted up high.

If you’re far away from two towers that are in very different directions, you may need to use a rotator, which has a motor to move your antenna to the proper direction. This obviously makes channel-surfing rather slow. Another option is to combine two antennas, but this can be rather tricky. See this webpage for more information.

Being close to the tower isn’t necessarily an advantage, because of multipath – it can mean you just get worse multipath interference. If you’re within a few miles of the tower, you can put a small, cheap attenuator in-line in your cable to reduce the signal strength.

Now that you have an idea of what your antenna is up against, its time to choose an antenna. Be skeptical – they’ll all have color-codes and most have mileage ratings; these are best-case (nothing between transmitter & antenna), so you’re not likely to get those. The more obstacles between you & the towers, the better antenna you need. The antennas that look like UFOs may be pretty, but don’t tend to get as good reception as the ones that really look like traditional UHF antennas. If you have neighbors that have antennas, you can make it easy on yourself and just find out what they’re using! There’s no magic antenna that works in every case, so try to find the one that will give you the best chances for your location – and if possible buy it locally where you can return it if it doesn’t work out.

Antenna placement is at least as important as your choice of antennas. You’ll probably have to try different locations (and possibly locations) to get good results. Don’t permanently mount it (or drill holes in the walls!) until you’ve found a location that works well. For me, "tweaking" consisted of moving it within the room one time (its not necessarily hard!). Depending on where your towers are, some channels may like one antenna location and other channels another; you may have to look for a middle ground. If the reception still isn’t very good, a pre-amp might help. Cheaper pre-amps often just make matters worse, though. If you have any questions on antennas, a good place for questions is the antenna forum on Home Theater Spot or the HDTV hardware forum on AVS Forum/

Step 5: Enjoy!

HDTV

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