What are the pros and cons of adding a second indoor cellular antenna?

Cell boosters. Everyone needs them. Even after all these years I’m surprised they aren’t in every home. I would have expected that all those tech-happy new homes you see being built would have them. I don’t know what the issue is, but all I can tell you is I certainly blog about them enough. It isn’t me.

The good news about cell boosters

When you buy a cellular signal booster, you get everything you need. It’s actually required by the government. You get the booster, the outdoor and indoor antenna, and all the cable you need for an average installation. But of course, this is Solid Signal. This isn’t where average people come. You, my Solid Signal faithful, are the sort who want to experiment. You want to get the most out of your purchase and you aren’t afraid to do a little work. So let’s dive in.

Why would you add a second cellular antenna?

Cellular transmissions are just like other radio waves. They come from a central point and go out in all directions like ripples in a pond. The problem is, most houses aren’t circular. Not only that, you’re probably not putting the cellular antenna right in the middle. Even with the most powerful boosters, there could be parts of the home that the boosted signal doesn’t reach.

Another reason to add a second antenna is to get past obstructions built into the home. Let’s say the cell antenna is on one side of the house. You’re on the other side of the house and the kitchen is in the middle. Kitchens are rough on cell signals. There are a lot of wires in the walls. The oven and refrigerator are big metal boxes that don’t let signals through. Decorative tiles are often tinted with metals that scatter signals. Not only that, if you got into that trend of using metal tiles on the walls or ceilings a few years ago, that’s going to make things even worse.

The bottom line is, a second antenna makes sense if there’s an area of the home that isn’t benefiting from having only one.

What additional antennas should I get?

There’s a decent selection of kits here at Solid Signal. For home use, you should be looking at the 75-ohm versions. The 50-ohm versions are for commercial use. However, if those aren’t appealing or you have a special need, you can really build your own kit. Start with a 75-ohm antenna,  and add virtually any splitter and RG6 cable. You’ll just need to know the pros and cons.

The pros

Obviously adding a second antenna is going to give you more coverage where you need it. It’s going to let you tailor the output of those antennas better to cover a rectangular house. It’s very easy to do this sort of thing and you don’t need to worry about one antenna interfering with another as long as you put the second antenna in an area the first can’t really reach. (That’s the point, right?) This is an inexpensive upgrade and very easy for your average DIYer.

The cons

There’s an old saying that “there ain’t no such thing as a free lunch.” When you split a signal, you don’t get two signals that are each as strong as the original. Just like you’d expect, signal strength after the splitter is about half what it was before the splitter. The splitter itself actually saps a bit of it, too.

Running a longer cable to a distant part of the house will also take away signal strength. Unless you’re running 200 feet or more, this isn’t a big concern, but it is a concern nonetheless.

The loss you introduce in the line can’t be compensated for, either. Inline cellular amplifiers aren’t legal in the US because of the potential that they’ll break the entire system. I suppose a smart DIYer could find a bidirectional amplifier in the right frequencies and adapt it, but just be careful. It doesn’t seem like a tiny little amp could be dangerous, I get it. However an overamplified signal can bring feedback into the system and that would cause it to shut down to avoid bringing down the whole cell network.

Should you split your cellular antenna signal?

In the end it’s up to you. I think it does make sense. We do it all the time in larger installations and if you’re comfortable with doing it yourself there’s no reason not to. Just be careful and be smart, and you’ll be ok.

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About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.