The Over The Air (OTA) TV Antenna Guide

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The Over The Air (OTA) TV Antenna Guide

Remember back in ancient times when you needed to improve your television’s over the air or OTA TV reception and Mom or Dad would adjust those long metal sticks on top of the television?  Maybe your house was at the forefront of technology and they turned a dial to position the massive erector set on your roof until the reception cleared.  It seems so quaint now, but we could all watch TV for free. Did you know you can still OTA TV for free?  Did you also know that OTA TV signals are in crystal clear HD? Furthermore, it’s free!  All you need is an OTA TV antenna and digital tuner.Published By

This article details how to watch network television using over the air digital broadcast 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 cord cutting guide.

Remember back in ancient times when you needed to improve your television’s over the air or OTA TV reception and Mom or Dad would adjust those long metal sticks on top of the television?  Maybe your house was at the forefront of technology and they turned a dial to position the massive erector set on your roof until the reception cleared.  It seems so quaint now, but we could all watch TV for free. Did you know you can still OTA TV for free?  Did you also know that OTA TV signals are in crystal clear HD? Furthermore, it’s free!  All you need is an OTA TV antenna and digital tuner.

Typically, readers will already have the digital tuner.  Any television made after 2007 should have one built in.  If your TV is older than 2007 and you aren’t ready to upgrade, that’s a topic for another article.

The other component we need is a TV antenna.  Before we continue, check if there is an antenna already on your roof.  If so, ensure it’s connected to a grounding block.  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.

If you weren’t lucky enough to find an antenna on the roof, we will need to figure out another solution. There are typically two types of people I encounter when it comes to the topic of antennas and HD TV.

There are those that just want to over the air TV quickly and easily. Then, there are those that desire to learn a bit about TV antennas, broadcast signals, and take everything into consideration before making a decision.  I plan on examining those details in this article, but first let’s help the people trying to watch OTA TV for free as soon as possible.

I Need to OTA TV Now!

There are countless variables involved in signal reception, making it difficult to recommend a perfect solution without knowing all those variables for your specific situation.  The strength of the signal around your house is an important key variable.

To figure out which channels you can receive use this tool from www.tvfool.com. Enter your address and choose 8 feet for the antenna height.  It will produce a report that lists the over the air TV broadcasters in your area, and how far the address you input is away from the broadcaster’s tower.

The report also provides a color coded table to give an idea of which antenna you will need.  For those that have no desire to delve into the details, find out if the major networks (ABC, CBS, NBC, and FOX etc.) are in the “green” section.

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Generally you should be able to capture channels highlighted in green with an indoor TV antenna.  If your address meets these requirements, you should get the most value out of a Mohu Leaf.  I go over how to get the most out of your Mohu Leaf in my Mohu Leaf Review.  You may also want to look at the Mohu Curve.  It comes with an amplifier to give it a bit more range, and it’s definitely the most attractive indoor ota TV antenna I’ve seen.

The Over the Air TV Antenna Guide

For those that can’t use the quick fix prescribed above, or need an optimal TV antenna solution, you will still require the report from www.tvfool.com. Though cryptic, there is useful information in this report. Below are concepts we need to be aware of to read the report. They will allow us to setup the TV antenna for optimal reception, thus receiving the most OTA TV stations possible.

Path – This is a description of the signal path from the tower to the TV antenna.  The height placement will affect the type of path the antenna can receive. This is the last column under the “Signal” heading of the report. Below you will find the values found in the columns and their definition.

  • LOS – This means Line of Sight. Basically, there is nothing in the way of the antenna and the tower.
  • 1Edge – When the signal leaves the tower it is “cut” when it hits a hill, mountain, or other well defined obstruction.  When this happens, the obstruction acts as a secondary, albeit weaker, source of signal generation. A value of 1Edge in the “Path” column indicates the antenna is receiving the signal after being cut by this obstruction. The picture below demonstrates this concept.
  • 2Edge – This is the same concept as 1Edge, except the signal was cut twice before reaching the antenna. As you may have guessed, this results in a much weaker signal than 1Edge.
  • Tropo – This is tropospheric scatter.  Basically the signal has been refracted by the high level of moisture in the upper troposphere.  Let’s not worry about these as they wouldn’t be cost effective to capture.

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Noise Margin – This is the first column under the “Signal” heading of the report and is denoted by NM.  This is the ratio by which the broadcast signal exceeds the minimum amount needed for proper operation, just before being picked up by an antenna.  In order for the channel to be received, the noise margin needs to be above 0 when it reaches your TV.   I recommend 10 dB to account for weather and other anomalies.

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 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.

Now that is out of the way we can address the business at hand.  Return to the TV Fool website and run a report for your address, and set the height to the height of your television.  I recommend printing it for ease of use.  Note the channels you require, by following the same instructions in the “I Need to Watch OTA TV Now” section above.   Directly under the channels table there are two boxes indicating which networks are VHF and UHF.

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If all the channels are VHF, have a Path of LOS, and are within 0 – 15 miles, try hooking up a set of “rabbit ears”.  Those may be enough.  If that’s not enough, we need to figure out other options. First let’s examine if an indoor antenna will work in your environment.

Can I Use an Indoor TV 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.

Watch Free TV in HD

  • 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.

To figure this out refer to the channel table report once more.  Now we are looking under the “Azimuth” header. Find the number under magnetic (Magn).  Note the number next to each.

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.

Types of Antennas

Directional, Bidirectional, Omnidirectional

Directional – This is an OTA antenna that is designed to capture signals better from one direction, which means that it will not pick up OTA signals well in other directions.  You can use this to target a specific direction maximizing the ability to capture the signal.  If all the stations are on the same azimuth or within 5 degrees of a midpoint, a directional antenna is a great option.  Otherwise you may need to move the antenna every time you tune in to a station with a tower in a direction not on that azimuth.

Bidirectional – This is essentially the same as directional, except it can maximize reception of OTA signals in front and behind the antenna.  For example, if you point to a station with an azimuth at 20 degrees, you should be able to pick up a signal in range at 200 degrees without moving the antenna.  To figure this out just add a 180 degree turn to the azimuth of signal you are aiming.

Omnidirectional – These antennas are designed to receive OTA signal equally from all directions.  The only drawbacks are, you can’t target a specific signal and there is typically no coverage directly underneath the antenna.  However, that isn’t a problem for indoor applications.  It’s important to understand that directional antennas will have a better range, but for typical indoor and outdoor home antennas, I would stick with the ease and convenience of an omnidirectional antenna.

Omnidirectional Antennas

Loop – A loop is an omnidirectional antenna and is shown in the picture below.  This antenna also contains a pair of rabbit ears.  The loop is mainly designed to pick up UHF.

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Dipole Antenna – For TV antennas, these omnidirectional antennas are typically referred to as “rabbit ears”.  They work for local VFH signals, but not much else.

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Bow Tie – The bow tie antenna is pictured below. It’s omnidirectional and can pull VHF and UHF.  The bow tie underperforms on UHF compared to the loop antenna, and doesn’t hold up to rabbit ears for VHF.

over the air tv

Flat– This is the aesthetically pleasing antenna pictured below.  They are easy on the eyes. They work well with UHF signals, and they are about equal to a pair of rabbit ears for VHF.

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Which Antenna to Choose

Now that we know the different types of antennas, we can review which one will work best for a given situation.  Below I’ve listed some possible scenarios and my advice for each after accounting for signal loss.

All my signals Are VHF and LOS – This is rare, but don’t spend any money. Rabbit ears may suffice.

My VHF signals are LOS and UHF are within 30 miles – You can try the loop-dipole combo, which is shown above in the “loop” antenna description.  A Bowtie with rabbit ears may be another good option for this situation.

All my signals are UHF and within 30 miles – Try using a loop antenna.

I need a pretty OTA TV antenna – Try the Mohu Curve antenna.  It works as well as a loop antenna on UHF, and can pull VHF.  You can check out my Mohu Curve review for optimal installation instructions.

Still no Reception?

As I said before it’s tough to recommend a perfect antenna solution due to the amount of variables being in play. You may still have success indoors by increasing the height of the antenna.  Return to the TV Fool signal analyzer and enter a higher value for antenna height.  Run the report and compare the new results with the height previously entered.

If you’re still having trouble I recommend installing the antenna at the highest point in your house on the wall facing the furthest tower you require. A number of people install antennas in the attic and that cuts out a sizable amount of signal loss between the tower and antenna.  If all your signals are on the same azimuth, you can try targeting the signal with a directional indoor antenna like the one pictured below.

tv antenna guide

The best option, if it’s available to you, is on the roof.   The same principles outlined for selecting an indoor antenna apply to an outdoor antenna.   There are dipole, loop, and flat antennas that are designed to be installed outdoors. The benefit of installing outside is elimination of any possible loss when the signal enters the house.  The benefit of installing on the roof is height.  Return to the TV Fool signal analyzer and enter your roof height and run the report.  You should have even stronger signals listed now.

What 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.

Cut the Cord

Hopefully found this post helpful,  and you can now watch tv for free in crystal clear HD.  If so, you have accomplished the most difficult step in dropping your cable bill and becoming a cord cutter.  If you want to learn more, check out my comprehensive guide to cutting the cord and stop paying for cable.

Source: http://groundedreason.com/watch-tv-free-antenna-guide/


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