How to Choose the Right HDTV Antenna

How to choose the right HDTV antenna

If you’ve never experienced over-the-air TV, then finding the right outdoor HDTV antenna can seem daunting at first glance.

Antennas come in all shapes and sizes. They range from small indoor units that you shove in the bookshelf behind your TV, to large 8-element bowtie antennas you mount atop a mast on your roof.

But how do you know which type is right for you?

Research is usually the first thing you do. But once you’ve grasped some basics about how OTA television works, your purchase decisions will become easier and simpler.

In this article, I’ve collected tips and recommendations to help get you started. You’ll better understand how antennas function, and which factors are most important in deciding which one to buy.

3 Reasons Why You Should Use a TV Antenna

The Federal Communications Commission has mandated that everyone should have access to free television over the airways.

As a result, OTA signals:

  • Are free to receive
  • Are found nearly everywhere
  • Offer unparalleled picture quality that's superior to cable and satellite, since these latter technologies use compression to pack in hundreds of available channels.

You can get this OTA programming by simply installing a TV antenna and hooking it up to your television.

In terms of cost, TV antennas are generally affordable, but you’ll pay for the labor if you hire a professional to install it for you. A reliable estimate of the cost of installing a TV antenna is around two to three months of cable or streaming services.

How TV Antennas Work

In basic terms, a TV antenna is a set of metal rods (i.e., dipoles) that “catch” electromagnetic waves travelling outwards from a transmission tower. 

In the television world, these waves are known as “radio frequency” or RF signals. These are your basic TV signals.

RF signals emanate outwards from a tower like waves rippling away from a stone dropped in a pool. Each wave starts off strongly, with a certain amount of energy as it travels outwards in a straight line.

But it gradually loses energy — due to distance as well as to being weakened by objects in its path, like forests and hills. Eventually it fades and disappears altogether.

Signal Frequencies: UHF and VHF

As TV signals travel outwards at the speed of light, they’re oscillating like regular waves whose heights and lengths change at a speed known as frequency.

“Frequency” is very important in describing and classifying TV signals. There are two types of frequencies:

  • Very high frequency (VHF): VHF signals for television are oscillating at a rate of 41 – 250 MHz. 
  • Ultra high frequency (UHF): These oscillate at a rate of 470 – 960 MHz, which is much faster than VHF, with shorter wavelengths as well.

Comparison wavelengths of UHF and VHF signals

Stepping back to the early days of television, stations used to broadcast analog TV signals on VHF frequencies.

VHF signals travel farther and are less weakened by interference than UHF signals. But the higher frequencies of UHF provide greater bandwidth for more TV programming.

Digital TV Channels

With the transition to digital TV in 2009, most television broadcasts shifted from VHF to UHF.

While stations had to correspondingly boost their transmission power output to reach the same number of OTA television consumers (due to greater attenuation or loss of UHF signals), they could simultaneously pack more programming into these higher frequencies.

Today, digital TV is broadcast using a system of real and virtual channels

Real Channels

Real channels (also known as radio frequency, broadcast, or digital channels) are shown in the table below. A real channel also corresponds to a particular frequency within the UHF or VHF bands.

Frequency

Real (broadcast) channels

VHF (low band)

2 - 6

VHF (high band)

7 - 13

UHF

14 - 51

(Notice there’s no low or high band UHF — this is because TV in North America uses only the low band.)

Virtual Channels

Now, each real channel represents a television station and is mapped to a number of virtual channels. For instance, WNBC in New York is broadcast on real channel 36 (UHF) and on virtual channel 4.3.

Virtual channels are designated by a decimal point (or a dash).

In the example of WNBC and real channel 36, other TV stations are also using that same real channel, but broadcasting on the other virtual channels (like 4.1, 4.2, 4.4, and so on).

Another difference between real and virtual channels is that you’ll see only the virtual channel on your screen.

This has some marketing advantages for TV stations. In fact, WNBC is known locally as “channel 4,” and is publicly identified as channel 4-3.

Antenna Design

Let’s talk a moment about hardware.

Antennas are designed to pick up certain frequencies. To be specific, an antenna’s size and type is a function of the size of the wavelength it’s trying to detect.

To be effective, an antenna has to be around half the size of the wavelength it’s receiving.

Since VHF wavelengths are twice as long as those of UHF signals (remember the diagram above), antennas for VHF will be larger than their UHF counterparts.

Antennas and Frequencies

We spoke about channel numbers above, and how it’s the virtual channel you see on your TV. Real channels, however, are more relevant to antennas. They reflect the frequencies that the antenna is designed to receive.

When buying an antenna, you should first understand which real channels it can pick up. For example, the Winegard Platinum Series HD7694P picks up UHF and high VHF. This means real channels 7 – 51.

That’s why you should know the available real channels being broadcast in your area before buying an antenna. Downloading and understanding your signal report before the purchase will save you the headache of reading your new antenna’s return policy.

What’s the Best Antenna for Free TV?

I’m going to level with you.

The best HDTV antenna you can buy, that reliably gives you all the free, over-the-air programs available in your area in crisp and clear high or standard definition format, will depend less on the antenna itself and more on your location (and corresponding signal strength).

That’s right; it’ll mostly depend on a few things having little or nothing to do with antenna technology.

I’ll explain these factors below. But first and foremost, you’ll want to buy an antenna that most perfectly matches these factors, once you’ve noted them.

So here are the points you should pay attention to when shopping for an antenna:

  • Where are the local sources of my TV signals?
  • What are their broadcast frequencies?
  • What are possible sources of interference that can prematurely diminish the quality of my signal?
  • What are the types of TV antenna I can buy?

Finding Over-the-Air TV Signals

In the above paragraphs, we looked at how TV signals travel through the airways and how antennas work.

Now let’s focus on a related, but more concrete topic: where are the sources of local TV signals being broadcast in your area? This is another way of asking, where are the nearest transmission towers located around you, and how far away are they?

Transmitter Location

If you study signal reports for different areas of the country, you’ll immediately notice some differences between urban and rural areas.

In urban areas, transmission towers are strategically placed to offer the best signal to the largest number of people. There, you’ll often find transmitters grouped together for convenient reception by TV antennas.

These groups of towers offer a wide range of channels and programming, and all you need to do is point an antenna in their direction to get all those channels.

TV broadcast towers

Rural areas are another story.

In places of fringe reception, transmitters may be scattered haphazardly around your location.

Take a look at this tvfool.com signal report for Boerne, Texas.

Signal report Boerne Texas

TV station frequencies in Boerne Texas

You might point your antenna towards the southeast quadrant to get six channels. But if you’re using a unidirectional antenna like a Yagi type, you’ll probably miss the channels in the northeast quadrant.

That’s unless you get a multidirectional antenna (with up to 180-degree reception) — more discussion on these antenna differences below.

Transmitter Distance

Next, you need to look carefully at how far away the transmitters are.

To continue our example, you might have considered pointing your Yagi antenna at the stations in the southeast quadrant.

The rest of the signal report reveals that out of those stations, only one (real channel 18) is less than 50 miles away.

This means you’ll need an outdoor antenna to pick up the rest of those channels.

All antennas sold today are rated for a given maximum range of reception. But I have my own rule of thumb when assessing an antenna’s ability to pick up distant towers:

When looking at an antenna's range for your situation, you should halve its maximum distance and check whether towers still fall within this range. If not, consider an antenna with greater range.

Channel Frequencies

Now let’s take a look at the channels themselves. The real channel numbers in the signal report are associated with certain frequencies.

TV Fool real channels

Going back to the example above, the majority of channels in that southeast quadrant are UHF. Channel 12 (KSAT-TV) however is high VHF, so you’ll need an antenna capable of high VHF if you want this channel.

So far we’ve been able to extract a lot of useful information from the tvfool.com signal report. You can get similar information from DTV/maps as well, though it’s presented differently.

Types of Television Interference

Interference is the presence of unwanted signals that distort or disrupt your television reception.

It’s like having a bad guest who spoils a good party.

You may be able to enjoy all your OTA channels despite interference, however, but it’s important to understand the sources that act to weaken, or even suppress your channels entirely.

Woman in front of TV experiencing interference

You can think of these as factors that are:

  • Outside of your home, such as hills, forests, atmospheric conditions, tall buildings, the use of adjacent or overlapping frequencies for radio communications, and so on
  • Inside your home: Examples include the structure of your house (building materials, radiant barriers, etc.), older household wiring that leaks electromagnetic noise, etc.

An exhaustive list of such interference factors is beyond the scope of this article but you can find complete descriptions elsewhere, such as on this page.

There is hope in mitigating these factors, though.

You can overcome many types of interference mainly by:

Antenna Gain and Directionality

An antenna with sufficient receptive power can often pick up a signal that’s weakened by both distance and interference.

Antennas are passive receptors, and so their size, shape, and number and placement of elements such as dipoles, reflectors, etc. — in short, their design — provide a certain ability to receive OTA radio frequency transmissions and convert these into electrical power for input into a TV.

This ability is referred to as antenna gain, and is typically measured in decibels (dB) or in some related format, like “decibels relative to an isotropic antenna (dBi)” which for our purposes is really just equivalent to dB. You can often find references to “gain” in antenna review articles both on this site and on others.

High gain outdoor antenna

For instance the Antennas Direct DB8e has an unamplified antenna gain of 17.4 dBi, which is one of the highest on the market.

The gain of an antenna is associated with its directionality, which describes whether it receives signals from certain directions, or from all directions.

Directionality is important because it means that a “directional antenna” (i.e., uni- or multidirectional) has a relatively narrow reception beam width that gives it a focus in certain directions. Such antennas are typically high gain.

On the other side are omnidirectional antennas. These receive signals from all directions, but lack reception focus in any particular direction. Such antennas typically have low antenna gain, because you can say their directionality is uniform in all directions.

As already mentioned, antenna gain is inherent in its design, and isn’t the result of electrical amplification — if you install an amplifier on the antenna’s coaxial cable to your TV however, then you’ll be adding amplifier gain to the line.

Types of TV Antennas

Let’s now take a look at the three main types of antenna, and understand the differences and similarities of each.

You can pretty much classify all TV antennas in the consumer market in terms of their directionality.

1. Omnidirectional Antennas

Omnidirectional antennas pull in signals from 360 degrees around equally well, provided these are at similar distances away and at similar signal strength.

Because of this lack of directionality focused in any single direction, these types of antennas need unobstructed access to a strong signal.

Indoor antennas are almost always omnidirectional. Customers typically place these just about anywhere and take less care in positioning them vis-à-vis signal sources, and they’re often amplified to compensate for their low antenna gain.

Pros of Omnidirectional Antennas

  • Capture signals from all directions
  • Compact in design, and can be mounted in different places around the home
  • Works well for areas with multiple towers located in many directions

Cons of Omnidirectional Antennas

  • Requires strong signal
  • Needs relatively unobstructed access to signals
  • Unsuited for areas of fringe reception

Examples

As already mentioned, indoor antennas tend to be omnidirectional. A few models of outdoor antennas that are omnidirectional exist as well, such as the 1byone New Concept Series.

Rabbit Ears

Once popular, “rabbit ears” are indoor antennas that are omnidirectional. You can manually adjust the dipole antennas to improve reception of any given channel.
Rabbit ears dipole antenna

Flat Panel Antennas

Today’s indoor antennas are sleek, square designs that discreetly fit into all kinds of nooks and crannies in your living room, or on a window sill. Such antennas are simple plastic shapes that are relatively flat, such as this AliTEK J-001 Amplified Indoor TV antenna.

2. Multidirectional Antennas

A multidirectional antenna can pull in signals from a wide angle, but aren’t omnidirectional. Some companies market their multidirectional antennas as being able to receive from towers up to 180 degrees apart, while others claim their antennas can receive up to 120 degrees.

A good rule of thumb is not to expect more than 180-degree reception from a multidirectional antenna.

Multidirectional Reception Angle

Multidirectional reception angle

 

Pros of Multidirectional Antennas

  • Suitable for areas of fringe reception with multiple towers at wider distances apart
  • Doesn’t require strong, unobstructed signals
  • Several styles available to accommodate different reception needs

Cons of Multidirectional Antennas

  • Lack of aesthetic appeal; generally taller and wider than other antenna types
  • Must be aimed in the direction of towers

Examples

Multidirectional antennas are often distinguished by their large mesh reflector panels. These panels help to focus received signals and support a wide angle of reception for the dipole elements.

Below are two typical multidirectional antenna designs.

Bowtie

Antennas with multiple bowtie dipole elements are the most common types of multidirectional antenna, such as the Antennas Direct DB8e Bowtie HDTV antenna.

Grid Antenna

These feature a wide, parabolic grid reflector resembling a grill.

Grid TV antenna

A benefit of this type is that it has very good reception (on par with a parabolic antenna used for satellite TV), but is less susceptible to strong winds as these pass through the grill.

3. Unidirectional Antennas

Unlike the previous antenna types, unidirectional antennas focus reception in a certain direction. The one characteristic you’ll notice about unidirectional antennas is their protruding axis, that you aim towards TV towers.

While precise aim is important, manufacturers often claim a reception beam width of 40-90 degrees. This means you should be able to pick up line-of-sight stations within this reception zone.

Unidirectional Reception Angle

Unidirectional reception angle

 

Such antennas feature high antenna gain, making them often ideal for areas that are less urban and have weaker signals.

Pros of Unidirectional Antennas

  • Works well for reception from distant towers
  • Powerful directional reception

Cons of Unidirectional Antennas

  • Must be aimed in direction of towers
  • Rotation or stacking may be needed for receiving from multiple locations

Examples

Two typical unidirectional designs are:

Yagi

Based on the Japanese Yagi-Uda design, these antennas consist of several elements of the same length along an axis. These elements generate radio waves that enhance gain in a single direction. A good example of a Yagi antenna is the ViewTV DA-290 Indoor/Outdoor Compact HDTV antenna:

Note that the Yagi part is actually the four (UHF) elements in front — the wider elements in the back are for VHF reception. Combining different antenna designs (e.g., Yagi with log periodic) optimizes reception and is a common practice among manufacturers.

Log Periodic

These antennas similarly feature high gain but also capture a wide band of UHF and VHF frequencies. Antennas that are exclusively of log periodic design aren’t as common as Yagi antennas in the consumer market.

Log periodic TV antenna

Many Yagi designs, however, such as the RCA ANT751R Compact Yagi HDTV antenna combine both Yagi and log periodic elements.

Summary

A TV antenna can be a wonderful option for those who enjoy television but don’t want the high expense of a cable or streaming service.  Understanding how antennas work and the critical factors that go into choosing the right one is vital for making your purchase decision both economical and enjoyable.

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