Don’t fall for this myth about digital TV antennas

You will need a digital antenna if you want to watch free local TV channels at home. However, buying one is a bit of a minefield. One could claim to give you 150 miles of range, another 600, another 5,000, all from a plastic base inside your home.

If these claims make you instantly skeptical, your instincts are correct. The reality is that television signals have physical limitations, and as much as marketers try, no antenna can overcome the curvature of the Earth. Before purchasing an antenna with the highest mileage, it’s worth taking a look at what actually determines how far you’ll be able to get a usable signal.

If you head to Amazon and search for digital TV antennas, you’ll see results including indoor antennas with ranges ranging from hundreds to thousands of miles. The worst offender is the one that claims to offer 6,000 miles of range. To put this into context, the distance between London and Los Angeles is approximately 5,454 miles.

No antenna in the world allows you to receive the BBC in Los Angeles. That doesn’t give you 1,000, or 500, or even 150. It’s also not about power, because TV transmitters can broadcast a strong enough signal. Instead, to watch live local TV, you’ll need a reasonably clear line of sight to the transmitter.

When signals are transmitted from a transmitter, they do not follow the curvature of the earth. Instead, they travel outward. The Earth is curved, so distant transmitters will eventually disappear below the horizon. Once a transmitter is beyond the horizon, its signal can no longer provide reliable direct reception. The horizon blocks the path. Atmospheric conditions might cause it to bounce a little further, but not by far. You also have buildings, trees, hills, mountains and more that can degrade the perfect line of sight, further reducing signal distance.

A digital antenna simply picks up the VHF and UHF radio frequency signals used to transmit encoded digital television. Digital broadcasting cannot eliminate these physical limitations, and there is no transmitter high enough to provide a range of 6,000 miles, or even 150 miles, even with an outdoor antenna in a perfect environment.

High gain antennas are also another marketing claim you will need to watch out for. Antenna gain describes how well an antenna can focus on a signal in one direction, which is especially important for outdoor antennas, but it does not guarantee better range.

There is no definitive answer to how well a digital antenna can pick up a TV transmitter’s signal. The environment, terrain, transmitter height, and signal strength all play a role in limiting a TV signal from the transmitter before you even start thinking about the antenna, because your environment (and any physical obstacles) will determine the range.

Suppose you are using an indoor antenna. One For All, a brand selling TV antennas worldwide, says its indoor antennas have a range of 25 to 60 miles, but its “usual rule of thumb” is to only use one when you’re 15 miles from the nearest transmitter. It also recommends that homes surrounded by obstructions, such as trees or buildings, located more than five kilometers from the transmitter, should use an amplified TV antenna to amplify the signal a little more.

Outdoor antennas will allow you to receive signals further away. Placing the antenna outside means you reduce the last obstacle, the walls of your house, and installing it at a high level improves the line of sight between it and the transmitter. Antennas Direct suggests that 70 miles is the effective line-of-sight limit for UHF signals, with low UHF and high VHF signals able to pass a little further, for example. This makes these common marketing claims suggesting a range of 150 miles, or 6,000 miles, extremely unrealistic for live TV reception.

The FCC maintains reception maps for over-the-air digital television signals, but these are based on using an outdoor antenna at least 30 feet above ground level. As the FCC itself notes, indoor reception “may vary considerably.”

Unrealistic marketing claims aside, digital TV antennas can and do work, but before purchasing one you will need to consider your environment and determine the best type of antenna to purchase. Your environment has a significant impact on the operation of any antenna.

Start by checking the distance to your nearest transmitter. FCC reception cards are a good option here, but you can also check with local TV stations to see what they recommend. Use this as a base point. If you’re near a transmitter, an indoor antenna might work, but the farther away you are, with more obstructions like tall buildings and mountains, then an outdoor antenna will probably be the better option.

As we have already mentioned, amplified antennas exist. These work by increasing the strength of the signal received by the antenna before it reaches your TV. They help compensate for signal loss, but they don’t work miracles. You can’t amplify a signal if the transmitter power is too low or the distance too great, so keep that in mind.

Where you plan to install the antenna is also important. Indoor models are best placed near a window, or as high as possible for a clearer path to the transmitter. These days, indoor antennas are usually omnidirectional, but if they’re not, make sure you’re pointing them in the right direction. Thick, heavy walls can weaken signal strength, as can large appliances in its path. Outdoor antennas will partly solve this problem, but you’ll want to mount it as high as possible, pointing it in a general direction toward the transmitter. You should also make sure that the quality of the cable between the antenna and the TV is as good as possible: no breaks, short cables and as few connections as possible.

Most important, however, is to maintain a healthy dose of skepticism about all marketing. Ignore any mileage claims you see, because you’re not getting hundreds or thousands of miles of range with a TV antenna. If you’re not sure, make sure you buy an antenna that you can try and return, just in case it doesn’t work as well as you hoped.