The Ultimate Digital TV Antenna Guide

This article details how to watch network television using over the air digital signals. For a more comprehensive guide on everything, you need to know about enjoying all the TV and movies you want without a cable TV subscription, check out my guide to watching TV without cable.

Over the Air (OTA) TV signals are what many of us grew up watching before Pay TV convinced us all we needed cable. Did you know you can still OTA TV for free?  Did you also know that broadcast TV signals are in crystal clear HD? Furthermore, it’s free!  We can all watch local TV channels without cable, all you need is an OTA TV antenna and digital tuner.

The majority of you already have a digital tuner built into your TV. Any television made after 2007 has a built in digital tuner, as mandated by U.S. law.  If your TV is older than 2007 and you aren’t ready to upgrade, you can look into getting a digital converter box.

Before we continue, check if there is an antenna already on your roof.   Find the cable coming off your roof, and locate where it comes in the house.  Connect that cable to your TV and scan for channels. Be aware you should ensure the antenna is properly grounded. If you don’t have an antenna or need a better one, read on. Click on any of the topics below to navigate to that part of the article.

Contents of this Guide

How to Choose The Best TV Antenna
The Best TV Antenna for You
Important TV Antenna Topics
TV Signal Loss
Where to Install an Indoor Antenna

Antenna Gain Vs Amplifier Gain

How to Choose The Best TV Antenna

Different situations may require different TV antennas. This article will consider those variables and help you chose the best TV antenna for you or your family. First, you will need to get a signal report to see which channels are available to you.

Get a Signal Report

Signal power is one of the most important factors when choosing a TV antenna. To discover the signal power in your area use this great tool from tvfool.com. Once you enter your address, you should receive a signal report like the one below.

While the report is color coded to see which channels require an indoor vs outdoor antenna, there are a number of factors that this color coding doesn’t address. I’ll go over the details of what this report means in this guide. 

* For the purposes of this guide, you want to note the “Netwk” column. For every “must have” TV network in that column, write down the values below.

* Real TV Channel is in the “Real” column.  The channel that you see on your TV is the virtual channel.  Stations do this to keep their channel brand while broadcasting on a higher powered virtual channel.

* Noise Margin or NM (dB) is the amount of signal loss or attenuation the TV signal can withstand and still be received. Many things can cause signal loss and I cover that later in the article.  The important thing to know is once the noise margin hits 0, the channel will not come in.

* “Dist miles” is the distance in miles your house is from that channels TV tower.

* The true direction of the station or the “True” column is the compass direction the TV tower is located.

These values will help you pick the best TV antenna. Before covering my antenna recommendations there are a few things we should consider like indoor Vs outdoor, UHF\VHF, and the importance of direction and gain.

Indoor Vs Outdoor

An outdoor antenna will always be better at receiving TV channels than an indoor TV antenna. I always recommend going with an outdoor antenna when possible. However, you will usually be able to pick up a TV channel with an indoor antenna as long as the noise margin or NM (dB) column is greater than 40. The biggest is the difference between UHF and VHF channels.

UHF Vs VHF
TV channels are split on to three different bands. Channels 2-6 are on the VHF-Lo band. Channels 7-13 are on the VHF-Hi frequency, and channels 14-69 are on the UHF frequency. The majority of indoor TV antennas are designed to pick up UHF channels. 

Directional Vs Omnidirectional
Directional TV antennas are antennas designed to pick up signals in the direction you point them. Omni-directional antennas are designed to pick up channels in all directions. This tradeoff off is done by focusing the antenna gain, which is different from amplifier gain.

With a directional TV antenna, the gain is built into the TV antenna to focus reception in the direction. This gain is measured by adding the gain value of the antenna to the noise margin (NM db). For example, a channel with a noise margin of 30 in the TV Fool report can be read as 45 if you point a directional antenna with 15 dB gain toward it.

Omni directional antennas balance their gain to pick up channels in all directions.

The Best TV Antenna for You
Now that we have a general idea about the things that matter when it comes to antenna reception, we can get into the best antennas to consider for given situations. Of course, if you want to know more about concepts like noise margin, I go a bit more in depth later in this article.

UHF channels with NM above 40 dB
In this situation, you should be fine with an Omni-Directional indoor antenna. It’s possible for these solutions to work for VHF-Hi channels as well, given they are with no more than 10-15 miles away.

UHF channels with a NM below 40 dB
In these situations, I recommend an outdoor antenna. The type of antenna really depends on the channel locations and the noise margin. If the UHF channels have noise margins are above 15, but are in multiple directions you can use an omnidirectional antenna.

The noise margin also has to account for noise in the line (which I cover later in the article).  A noise margin of 15 should be more than enough,  but it’s possible you may need a bit more signal power.

UHF and VHF-Hi Channels
Not everyone will have the same experience due to interference patterns varying by location. If you are having issues receiving VHF-Hi channels there are antennas designed to do a decent job with both UHF and Hi-VHF channels.

Channels in Lo-VHF, VHF-Hi, and UHF
Some areas of the country have digital channels in the VHF-Lo range. These are channels 2-6 in the “Real” column.  

Important TV Antenna Topics
Now that you know the type of antenna you will need, I wanted to point you to more information on common questions that come up in regard to over the air television.

Over the Air DVR – Yes, you can record from your antenna. In fact, I strongly recommend it.

More than 1 TV – There are easy solutions for connecting an antenna to more than 1 TV. I recommend an outdoor antenna for this in most situations.

Grounding the Antenna – This isn’t a concern for an indoor antenna. However, you definitely want to ground an outdoor antenna. It will mitigate lightning strikes and other electrical anomalies that are possible, but unlikely.

Signal Loss
Signal loss comes from various sources and is measured in decibel (dB) loss.  I’ve done my best to examine various studies of signal loss and put together rough estimates of the possible signal loss below.  The following sources of signal loss would subtract from the NM;

TV – There is typically a dB loss associated with the TV. An estimate of 3 dB should suffice.

Cable runs – Typically RG-6 coax is used in the US.  The maximum DB loss in the highest TV frequency is about 5.6 dB per 100 ft. cable run.  Add a .5 dB loss for any un-split joint connection.

Splitters – Every split of the coax cable running from the antenna to a TV incurs the loss listed on the splitter.  This is typically 3.5 dB, but to be sure, it should be listed on the splitter. You have to count every output on the splitter whether it’s used or not. 

Adjacent House – An adjacent house in line with the generation of the signal and casting a shadow either on the antenna or on the exterior wall that is in the path of an indoor antenna creates a loss. Various studies show a dB loss between 10-21 dB for signals within UHF and VHF frequency.  Studies also show that raising the height of an indoor antenna will lessen the loss.

Tree Shadowing – This is when a  nearby tree in line with the generation of the signal casts a shadow on the antenna or on the exterior wall  in line with the antenna.  Trees have been shown in studies to have a dB loss of 0-10 dB within the UHF and VHF frequency. A TV antenna installed at a lower height can improve signal propagation since the signal can better avoid the tree canopy. In rare cases raising an antenna can actually degrade reception. Often in these cases a, dense tree canopy can be blamed.

Home Penetration – This only matters for an indoor antenna.  Expect a loss of around 14dB for a signal to penetrate a home and reach a first floor antenna.  Installing the antenna on the 2nd or 3rd floor can greatly mitigate a portion of these losses.

Anything else with a quantifiable decibel (dB) loss – Yes this is vague, but any nearby obstruction can cause a dB loss.

Where to Install an Indoor Antenna
To figure out if we can use and Indoor Antenna, we will first figure out the available Noise Margin after estimating the dB loss using the information above.  To do this, locate the NM field and find the lowest number for all the stations you require.

Locate the bull’s-eye chart to the left of the table pictured below.  Figure out where your antenna will be mounted in relation to that tower.

Optimally it will be near the exterior wall closest to the tower.  If this is the case, only subtract 14 dB for home penetration; otherwise subtract around 34 dBs to account for your house shadowing the signal.

* If there is heavy foliage that could cast a shadow on your antenna from the direction of the tower, subtract 10 dBs.

* If the adjacent house is in the direction of the tower and casts a shadow on the antenna subtract another 20.

* If you are left with about 12 dB or more after subtracting loss estimates,  you should have enough of a signal to watch OTA TV.  If you are below 12db try and find a higher area to mount the antenna.  This may be an upper floor, or even the attic. You may want to consider the roof if possible.  You can rerun the TV Fool report from a new height to test if it improves the signal.

If there is enough noise margin on the weakest signal, the next consideration is the distance of the antenna from the tower.  An important variable when considering the distance is whether the signal frequency is VHF vs UHF.  Commercial antennas typically indicate the range at which they can capture a signal.  It is a bit misleading as they usually specify the distance for Ultra High Frequency (UHF).

UHF frequency runs at a higher frequency than VHF or “Very High Frequency”.   Truth be told, there is little an indoor commercial antenna will do to pick up VHF that can’t be done with just a pair of rabbit ears.

Typically your VHF channels should be within 15 miles, and your UHF should be within 30 miles for an indoor solution to work.  This is extremely dependent on how much loss the signal takes before reaching your antenna. I have seen indoor antennas work over 50 miles from the broadcast tower.

The last concept we need to consider is direction.  We may or may not need this information depending on the antenna type, but it’s important to know in the event we need to troubleshoot the signal.

It’s also handy to circle the channels appearing on the bull’s-eye for ease of reference. Now we have everything we need to know about the signal.  We can now cover the types of antennas available and their strengths and weaknesses.


Antenna Gain Vs Amplifier Gain
This subject can be confusing as there are really two types of gain in relation to antennas. There is antenna gain, which we discussed earlier as being inherent to the antenna. It essentially aids you in receiving a signal from the tower and can be added to your noise margin.

Then there is amplifier gain, which is added from a powered amplifier. This amplifier will not impact the antennas ability to actually receive the signal, but will mitigate noise created by splitters, cable length, and tuners between the antenna and your television.

More about Antenna Amplifiers

Passive vs Active Antennas – An active TV antenna is an antenna that has a powered signal amplifier. This is opposed to a passive TV antenna, which are without signal amplification. Active antennas will not affect the antenna’s ability to pick up a signal.

However, it will boost a signal that reaches your antenna to overcome noise in the line, splitters and TV tuner. This “boost” is given in terms of a dB gain.  Please note that an amplifier also adds noise that will impact the gain of the amplifier.

This doesn’t mean every antenna needs an amplifier.  Strong signals that are boosted can actually overload the tuner causing the channel to no display on the TV.  (Overload in this instance doesn’t mean “blow up.”  The tuner will be fine)

There are also instances where an amplifier will provide no real benefit.  For instance, let’s assume all the channels received hit the antenna with 30 dB of noise margin to spare. That’s already plenty to overcome most coaxial runs to the TV, hence no need for an amplifier.

This brings up another important point. Clean up your coaxial runs.  Older antenna and cable TV installations used RG-59 coaxial cable.  That has almost double the dB loss of the RG-6 used in modern installations.

If using splitters, be sure they are rated at least 5-1000mhz. Remember that signal strength is divided by the number of outputs on the splitter, whether they are used or not.  A splitter causes a 3.5 dB connection loss on each output.

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