LTE Filters for TV antennas – What You Need to Know
If you're setting up your antenna system to watch (or are already watching) free, over-the-air television, you may have noticed a little gizmo on our Web site that we call an LTE filter (#CM-3201). You may also have noticed that we recommend that you install one to improve TV reception. "What the heck is an LTE filter?" you're probably wondering. "And why do I need one?"
Both good questions. We asked a third party industry expert to give us his take on LTE filters and how the Channel Master filter performed, here is what he had to say.
Let's start with the abbreviation LTE, which stands for Long Term Evolution. It's simply a way to describe the current generation of smartphone networks. (LTE is also known as 4G, and the newest technology is known as 5G.) Depending on how old your phone is, it will be compatible with LTE networks, which means it must work on LTE radio frequencies.
Here's where an LTE filter comes in. Over the past few years, the Federal Communications Commission has auctioned off more TV channel spectrum; more specifically, all UHF TV channels above 37 (above 600 MHz). Those channels can now be used for other purposes, and as it turns out, one of those purposes is mobile phone networks.
So, why is this a problem for over-the-air TV channel reception? Depending on your home's proximity to LTE towers, the strong signals they emit can overload the receiver in your TV and cause channels to drop out, or disappear altogether. It's kind like trying to have a conversation with someone on the other side of a room while another person is talking very loudly next to you. Your mobile phone can even cause TV interference if it operates on these frequencies.
The receiver in your television is designed to respond to a wide range of frequencies so you can have just as reliable reception on channel 35 as you do on channel 17. In fact, before the FCC auction, UHF TV channels went all the way to 51 (and before 2009, up to 69). Accordingly, your TV is quite sensitive to signals that fall into this range – which now includes those pesky LTE signals.
To solve potential reception problems resulting from LTE interference, Channel Master's thinking went along these lines: "If there aren't any TV broadcasts on channels above 36 now, why not just block all signals above that frequency from coming through?" And that's exactly what the LTE filter does – it sharply cuts off all signals above 600 MHz, which is about the upper edge UHF channel 36. And when they say "cuts off," they MEAN it!
Figure 1 shows a spectral plot of several UHF TV channels (to the left of center) and a strong LTE tower in operation (to the right of center). Notice how strong the LTE signal is – about as strong as the local UHF station on channel 28 (far left)! It's likely to cause interference to several of the channels shown, especially the relatively weak Channel 36 signal at the center of the screen.
Figure 2 shows the same view of TV channels from UHF 28 to UHF 36, after the Channel Master LTE filter was installed. Notice that the LTE signals to the right have disappeared completely – this "low pass" filter has effectively blocked them from getting into your TV, or any other televisions connected to your antenna system.
Installation couldn't be easier. To maximize performance, you should install the LTE filter as close to your antennas as possible. For outdoor installations, the filter should be installed before the input of antenna amplifiers, or ahead of splitters. For indoor antennas, simply install the filter at the RF connection of your television. That's it! And now you know…
Channel Master wants to thank our guest writer for contributing his thoughts and experience for this blog post. Come back and check our blog frequently, we will be interviewing more industry experts and even asking customers to share their interesting stories with us and our audience.
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NOTE FROM THE AUTHOR: All TV channel signal levels will decrease slightly when this filter is used. You may not notice any difference in reception after you install the LTE filter. However, LTE interference from a base station or your smartphone can happen at any time of day, and might affect your DVR recordings.