What is over-the-air TV?

Over-the-air TV — which also goes by the monikers broadcast TV, linear TV, and terrestrial TV — refers to television signals sent into the air via a TV station's transmission tower. As I discuss a bit later, those transmission towers are Earth-bound (as opposed to, say, an orbiting satellite), hence the name terrestrial TV.

To view the signal from nearby transmission towers, you need an antenna, which I discuss in detail in Chapter 4. You then connect the antenna to your TV and you're good to go.

Good for what, you ask? The answer depends on where you live and how close you are to an urban center. Generally speaking, you can expect some or all of the following when you tune in to over-the-air TV:

• Newscasts that feature coverage of local news, sports, and weather: Here, local refers to whatever urban center is host to the station transmitting the over-the-air signal.
• Live local sporting events.
• The full lineup of shows from most major broadcasters. In the United States, you should receive most or all of the following stations: ABC, CBS, the CW, Fox, NBC, and PBS. Other major broadcasters include CBC and CTV in Canada and the BBC in Great Britain.

• One or more national over-the-air broadcast networks, such as Home Shopping Network, ION Television, MeTV, or Univision.

  For a complete list of the over-the-air TV networks available in the United States, check out the following Wikipedia article: https://en.wikipedia.org/wiki/List_of_United_States_over-the-air_television_networks.

• Community-focused content such as public access channels, locally produced shows (live or prerecorded), and locally broadcast stations.

The number and variety of available channels depends on where you live. As a general yardstick, locations in or near major cities can often get up to 50 channels; locations in or near mid-sized cities might see around 35 channels; and locations in or near small cities might get around 15 channels. These numbers assume ideal conditions, so in the real world most folks get fewer channels.

The pros and cons of over-the-air TV

The pros of OTA TV aren't hard to find: free content, access to local news and sports coverage, and a relatively inexpensive and simple hardware setup.

Here's another item to add to the “pro” side of the OTA TV ledger: excellent picture quality, particularly if you're used to cable TV. The signals that come via cable are massively compressed so that the cable company can transmit more channels at once. That compression greatly reduces signal quality. OTA TV signals, by contrast, are only compressed a little, so the picture looks much better than it does on cable.

Are there any negatives to consider? Yep, a few:

• One word: commercials: Broadcast TV is free because it's supported by commercials, lots of commercials. Be prepared to make steady and heavy use of your TV remote's Mute button.
• Lack of viewing freedom: Unless you pay extra for a digital video recorder (DVR) that works with OTA TV (see Chapter 5), you have no choice but to watch OTA shows only when they air.
• Limited channels: Depending on where you live, your OTA equipment might pick up a few dozen broadcasting stations or just a few. Either way, you're facing a limited TV lineup compared to what you had in your cable days.
• No cable channels: By definition, OTA TV doesn't include any channels that broadcast via cable TV, so that means no HBO, no Showtime, no ESPN, and no CNN.
• No technical support: With an OTA TV setup, you're on your own when it comes to troubleshooting problems. Of course, if you're just coming from cable, you're used to having non-existent technical support!
• No channel guide: In a basic OTA setup, usually you can find out what's on only by flipping through the channels. I know: so primitive! Fortunately, you can peruse online TV listings, and for a bit of extra cash each month, you can add a channel guide to your configuration. Note, too, that an OTA DVR includes a channel guide, as do some TVs.

The television station

From the perspective of over-the-air TV, all signals begin at a television station. There are four main kinds of stations:

Whatever the station type, the TV content supplied by the station will be comprised of either or both of the following:

• Internal content generated in the station itself: This content could be a live local newscast or similar live-to-air programming or prerecorded shows, such as reruns of previously aired local shows.
• External content transmitted to the station: This content could be shows supplied by a parent national broadcast network — the so-called network feed — or live coverage of local happenings, such as sports or entertainment events.

The transmission tower

The station converts the content to a digital signal. Most digital signals nowadays are in high-definition (HD) format, although some stations might broadcast using the standard-definition (SD) format. In the future, many digital television signals will be ultra-high definition (UHD). (UHD is part of the ATSC 3.0 stuff I noted earlier in the “What Is Next Gen TV?” sidebar). Is all this gobbledygook to you? Then see the upcoming sidebar “SD? HD? UHD? What Is This Stuff?” for the 411.

That signal includes both the video and synchronized audio, as well as data such as the channel number, associated network (if any), and closed captioning information. The station passes the digital signal along to a television transmitter. The transmitter is usually a tall tower installed in a high position, such as on the roof of a building or the top of a hill. The broadcast tower then transmits the digital television signal as radio waves in all directions. This is the “over-the-air” part of over-the-air TV.

For a full-power station, the transmission tower will have a range of between 50 and 80 miles (80 to 128 kilometers); for a low-power station, the transmission tower's range will be between 15 and 30 miles (24 to 48 kilometers).

The antenna and tuner

Okay, so myriad television signals are flying around your head as you read these words. How do you redirect those signals from the air out there to your TV in here? To view over-the-air signals in your home, you need three things:

• An indoor or outdoor antenna to pick up the signals. See Chapter 4 to learn everything you need to know about selecting and installing an antenna to pick up over-the-air signals.
• A tuner integrated into a television or a similar device (such as a DVR). Note that the tuner must be capable of interpreting the television signal picked up by the antenna. For example, most television signals are transmitted in HD format, so your TV (or whatever) must have an HDTV tuner.
• A coaxial cable that brings the signal from the antenna to the tuner.

Figure 3-1 shows how the whole over-the-air TV process works.

Understanding the factors that affect signal strength

As mentioned, TV station transmitters have ranges as low as 15 miles (24 kilometers) for low-power stations and as high as 80 miles (128 kilometers) for full-power stations. However, the power of the original signal is only one factor that determines how strong the signal is by the time it gets to you. Here are some other factors that come into play:

• Your location: Most TV station transmitters are situated in or near urban centers. The bigger the city, the more transmitters it will host. If you live in a city, you'll likely receive a strong signal from most of that city's TV transmitters. The farther away you live from the city, the fewer signals you'll pick up and the weaker those signals will be.
• Your antenna's range: If you live 50 miles (80 kilometers) from a transmission tower and that tower is connected to a low-power station with a maximum range of 20 miles (32 kilometers), you're out of luck, right? Yes, if your antenna's range is just a few miles, as it is with most cheap indoor antennas. However, costlier outdoor antennas often have ranges up to 70 miles (112 kilometers), and such an antenna would pick up the low-power station no problem.
• Your antenna's direction: Cheaper OTA antennas are unidirectional, which means they pick up signals from only a single direction. If you have such an antenna, you'll get a greater signal strength from a particular transmission tower if your antenna is pointed at that tower.
• The line-of-sight between your antenna and local transmission towers: For the best signal quality, your antenna requires a line-of-sight with the broadcast tower. Line-of-sight means you could draw a straight line between your antenna and a transmission tower without going through a tall object such as a building or a hill. Line-of-sight might be a problem is you live in a valley or if your location is surrounded by tall trees.

• Objects that interfere with the broadcast signal: The signals you receive can be degraded by any number of modern technologies, especially the presence of nearby cellular network (especially LTE) towers or power lines.

  Having no line-of-sight with a broadcast tower or having nearby objects that interfere with the signal can produce weak or poor reception. However, more often than not, you simply don't receive the station at all, a phenomenon known in the trade as the digital cliff.

  If you have a nearby cellular network tower that might cause interference, you can install an LTE filter between your antenna and your TV. This device filters out interference from LTE cellular signals to give you better over-the-air TV broadcast reception.

• Today's weather: This one sounds like a joke, but it's true. Extreme weather such as heavy rain or snow, a peasouper of a fog, and wild swings in temperature can wreak havoc on a broadcast signal.

Now that you know what factors can influence a signal, you're ready to start looking around to see what's available in your area.

If you live in Great Britain, you can use an antenna — sorry, I mean an aerial — to access free TV content supplied by the Freeview platform. Freeview supports more than 80 channels, including the BBC, Sky, ITV, and Channel 4. To see which channels are available in your area, go to www.freeview.co.uk/check-channels-home.

Checking the FCC's digital TV reception maps

The Federal Communications Commission (FCC) regulates television (as well as radio, satellite, and cable) for the United States. The FCC website offers a DTV Reception Maps page where you can use your address or current location to bring up a list of nearby digital TV stations.

As you might imagine, since the FCC is a department of the US government, the DTV Reception Maps tool only works for US-based locations.

Here's how the DTV Reception Maps tool works:

1. Use your favorite web browser to surf to www.fcc.gov/media/engineering/dtvmaps.

2. Use the text box to enter your address.

   For the best results, include as much information as possible: street number and name, city, state, and ZIP code.

   Alternatively, you can submit your current location by clicking the Go to My Location! button. Note that your web browser might ask if it's okay to supply the page with your current location. If you're cool with that, be sure to click Allow or OK or whatever to give your permission. If you go this route, skip Step 3.

3. Click the Go! button.

   The website displays a table named DTV Coverage that shows the available over-the-air TV stations in your area, as shown in Figure 3-2. This data gives two indicators of signal strength — color and signal bars (in the first column). Here's how to interpret these indicators:

   • Strong signal: The station info has a green background and four bars.
   • Moderate signal: The station has a yellow background and three bars.
   • Weak signal: The station info has a brown background and two bars.
   • No signal: The station info has a red background and you see an X instead of bars.

   The DTV Coverage signal strength results are based on the assumption that you're using an outdoor antenna mounted 30 feet above the ground. If you're using an indoor antenna or an outdoor antenna mounted lower than 30 feet, your signals will be weaker than what the FCC shows.

   You also see your location marked with a pin on a map (not shown in Figure 3-2).

   

4. To try a different location on the map, click and drag the pin to the location you want.

   The page updates the DTV Coverage table for the new location.

Using TV Fool's TV signal locator

Probably the best tool around for checking out the available over-the-air TV signals in your neighborhood is the TV signal locator tool offered by the TV Fool website (www.tvfool.com). It works in both the US and Canada and gives you tons of information about each station signal.

To use the TV Signal Locator tool, follow these steps:

1. Point your web browser to www.tvfool.com.

2. In the Tools section on the left, click TV Signal Locator.

   The TV Signal Locator page appears.

3. Select the Address radio button and enter your location info using the Address, City, State/Province, and Zip/Postal code text boxes.

   If you're not comfortable giving TV Fool your full address, you can use a more anonymous method that uses latitude and longitude. Simply select the Coordinates radio button and specify your location using the Latitude and Longitude text boxes.

   Okay, I hear you ask, how do I get these coordinates? The easiest way is to surf to Google Maps (https://maps.google.com), and run a search for the location you want to use. Right-click the pin that shows your location. The top of the shortcut menu shows, in order, your latitude and longitude.

4. (Optional) Use the Antenna Height text box to enter the height, in feet, that your antenna sits above ground level.

   If you don't have your antenna yet and aren't sure where you want to mount it, leave this box blank. In that case, TV Fool uses a default value of 10 feet.

5. Click Find Local Channels.

   TV Fool mulls things over for a few seconds, and then returns the TV signal analysis report, as shown in Figure 3-3.

The main part of the report is divided into two sections:

• The radar chart on the left tells you the direction of each signal.
• The table on the right lists the available signals for your location.

The table lists the stations in descending order of signal strength. The results use the following color code:

The table has a Signal section that provides two useful values:

• The Path column tells you the path the signal travels between the tower and your antenna: LOS (line-of-sight) means a direct path to your antenna; 1Edge and 2Edge mean the radio signal is diffracted (bent) around some object to get to your antenna; Tropo means the (extremely weak) signal comes to your antenna after being scattered by the troposphere (the lowest layer of the atmosphere).
• The Dist miles column tells you the number of miles away the broadcast tower is from your location.

Real versus virtual channels

In the TV Fool report (refer to Figure 3-3), note that the table has a Channel section that offers the channel call sign and network, as well as two columns labeled Real and (Virt). Here's what these two columns are telling you:

• Real: The channel number corresponding to the frequency at which the channel is broadcast — the transmit channel or RF channel (see Chapter 4 for more about this).
• (Virt): The virtual channel number, which is the number you tune into using your TV remote.

Why are they different? Back when all channels were analog, many stations used their channel number as part of their brand. For example, Figure 3-4 shows the logo for WNBC in New York, which in the days of analog TV aired on channel 4. As you can see, the number 4 plays a prominent role in the logo.

The problem is, when TV signals switched to digital, the digital channel number assigned to some stations wasn't the same as the station's analog channel number. WNBC, for example, was assigned the digital channel 28. Of course, the marketing folks at WNBC and hundreds of other stations didn't want to throw out years of branding. The workaround was to enable these stations to create virtual channels corresponding to their original analog channel numbers. WNBC, for example, uses virtual channel 4.1. When folks in New York tune to channel 4.1, they see WNBC, even though the station is being broadcast on a completely different “real” channel.

Mapping digital channels to branded channel numbers is only part of the virtual channel story. One of the advantages that broadcasters gained with the switch to digital TV was the capability of transmitting multiple channels on a single broadcast transmission, which is why virtual channels use decimals, such as the 4.1 for WNBC in New York. The .1 means this is the first signal transmitted on this frequency. As it happens, the transmitter for WNBC also includes two other channels: Cozi TV, which airs on virtual channel 4.2, and NBC LX, which airs on virtual channel 4.3.

One of the problems with the TV Fool output is that it doesn't tell you about any of the extra channels provided by a given broadcast transmission. To see these extra channels, try an alternative tool such as AntennaWeb (https://antennaweb.org/).