We put one of these athletes through heavy compression to show the difference between OTA and cable quality. Krivosheev Vitaly/Shutterstock
It sounds ridiculous, but free broadcast TV offers noticeably higher visual quality than expensive cable. But they both operate at a 1080p resolution, so what gives? Why does a simple antenna get you a better picture than pricey cable TV?
Free TV Isn’t Just Sesame Street
Before we get into why OTA TV looks better than cable, we need to understand that OTA TV isn’t as useless as people like to imagine. In fact, there’s a chance OTA TV can comfortably replace your cable subscription.
Free TV isn’t just PBS and local news. Most of the major television channels (especially sports channels) simultaneously broadcast on OTA and cable TV. So, if you’re only using cable to watch networks like ABC, FOX, CBS, and NBC, you’re wasting about $1,000 a year on content you can get in higher quality with a $15 digital antenna. And in most cases, a cheap streaming service can supplement the channels you might lose by ditching cable.
Now that we’ve cleared the air let’s get down to the nitty-gritty. Why does cable look worse than free TV?
Compression Kills Cable Quality
The obvious difference between cable and OTA TV is channel-density. Cable TV is comprised of a few thousand channels, while OTA TV only broadcasts (at max) 69 channels for each locality. This difference in channel-density is the big reason why cable doesn’t look as good as OTA TV.
Most OTA channels (55 of the 69) sit comfortably on the 470 to 806 MHz UHF spectrum. This spectrum is divided for each channel, so each one has its own 6 MHz band. But 6 MHz isn’t nearly enough bandwidth for HD TV transmissions. So, broadcasters compress their video (reduce the file size) using the lightweight MPEG-2 codec, which leads to only a tiny loss in visual quality.
The image on the right is an example of how heavy compression leads to quality loss. Dean Drobot/Shutterstock
Cable TV occupies the 54 to 1000 MHz frequency range, with a big emphasis on the 750 MHz and 860 MHz bands. This giant frequency range (with a focus on high bands) translates to a lot of bandwidth—which means cable TV should look better than OTA TV, right?
The problem is the extra bandwidth is only used to host more channels. While OTA TV places just one channel on each 6 MHz band, cable companies use aggressive compression algorithms (like MPEG-4) to shove around 20 channels on each 6 MHz band. As you’d expect, this aggressive compression leads to a dramatic loss in quality. It’s kind of like shoving 20 movies on a single DVD.
If you’re having trouble understanding all this tech jargon (you’re not alone), think of radio frequency (expressed here as MHz) in terms of internet speed (MBps). Generally, 1 MHz is equal to 1 MBps. We would need to know what encoding schemes are being used by broadcasters to make an accurate translation, but this simple comparison can make things easier to digest.
Transmission Kills Cable Quality
You probably already know this, but OTA TV is just a local radio transmission that you pick up with a receiver. And while radio signals can technically travel forever, their intensity degrades over time. This degradation can lead to some quality loss, but if you have a correctly set up antenna (and maybe a signal amplifier to boot), the quality loss will hardly be noticeable.
Cable TV, though, isn’t exactly a local operation. It starts with the TV networks, which transmit their programs to local cable companies via satellite. (If you see a plot of land full of satellite dishes, it’s probably operated by your local cable company.)
The cable companies then compress these video signals and send them through the city via a network of coaxial cables. These video signals degrade as they travel through town, so they’re boosted by amplifiers along the way. Then, when the signal finally reaches your home, it has to be decoded by your TV. As you can imagine, each step in this messy process leads to quality loss. When paired with the aggressive compression used by cable companies, it’s a wonder cable TV looks good at all.
OTA TV Will Have 4K Before Cable
OTA TV already looks better than cable. But the difference might not be a game-changer for you—at least, not yet.
Right now, the FCC is transitioning OTA TV from ATSC 1.0 to ATSC 3.0 (we’re skipping the number 2). This change comes with a ton of upgrades, including the ability to watch TV on your cellphone to automatic channel scanning. But arguably, the biggest change is that ATSC 3.0 will support 4K TV. In case you’ve forgotten, cable TV is still stuck at 1080p.
Why doesn’t cable TV support 4K yet? Well, because cable providers got themselves into trouble by offering too many channels. There simply isn’t enough bandwidth on the cable spectrum to offer 4K TV. Cable companies are already compressing the hell out of their 1080p content, and 4K offers approximately four times the number of pixels as 1080p and double the resolution.
If cable companies decided to shove 20 different 4K channels onto a single 6 MHz band, they’d have to double down on compression, and the quality would look like absolute garbage.
So, if cable companies want to offer 4K, they’re going to have to either slim down their library of channels or buy up some more frequency bands. The FCC is currently licensing its available frequency bands to cellphone carriers in anticipation of 5G. The future doesn’t look too bright for cable.
Make the Most of OTA TV
There are some obvious drawbacks to OTA TV. Most of these will be solved after we’ve fully transitioned to ATSC 3.0. Until then, you’re just gonna have to work with what you’ve got. Here are some tips on how to make the most of OTA TV until ATSC 3.0 comes around:
Use an OTA Box: Like the TiVo Bolt, these add grid guides, DVR functionality, and smart apps to your antenna TV. Essentially, they make free TV more like cable.
Buy a Good Antenna: Cheap or built-in TV antennas work fine, but they don’t have a lot of range. We suggest buying a high-range digital antenna that’s ready for ATSC 3.0. This way, you get a lot of channels, and you won’t need a new antenna when ATSC 3.0 rolls out.
Check What’s Available In Your Area: Use a TV signal locator to check which OTA channels are available in your area. This way, you can adjust your antenna until you receive the channels you want.
Try a Signal Amplifier: If you’re not happy with your channel selection (or the channels you do receive look like crap), try a signal amplifier. These, essentially, boost the signals you receive. Just be careful, as signal amplifiers can over-amplify (and distort) good signals.
Rescan Often: As we transition to ATSC 3.0, every channel will move to a new frequency. If you don’t rescan your TV once a month, you’re going to lose channels.
Of course, you can always supplement your OTA TV with some streaming services. Netflix and Hulu are great, but you can also subscribe to streaming TV services—like Hulu Live and YouTube TV—if you want a more cable-like experience.