Should you put a flat antenna on the outside of the window or on the inside?

Flat antennas like our HDBLADE are so slender that they’re just begging to be put on the window. This is especially true with the clear ones that let all that sun shine through. But the question remains, should you put them on the inside or the outside?

Many newer windows come with UV coating that could potentially do a better job of blocking TV signals than a wall does. That’s the downside to all that protection from the elements. If you put a flat antenna up on a window, and it doesn’t work well, this could be the issue. In that case, try opening the window and positioning the antenna in the open area. If reception really improves, there’s your answer.

For the most part, flat antennas are not designed to work outside. They’re not weatherproof and they’re certainly not immune to UV radiation which will take its toll on the plastic parts of the antenna. In general it’s best to keep them indoors where they are happy. However, if it turns out that they work much better outside, and for some reason you don’t want to go to an outdoor antenna like the Flatwave Air, you could try mounting the antenna outside. (By the way, yes it’s true that the Flatwave Air is more expensive, and a lot of that has to do with the fact that it is actually designed to work outside.)

To do this, start with a flat antenna cable like this one which will let you run the cable through the crack between the window and wall without letting air in. Then, mount the antenna securely. If it’s a clear antenna, you can easily see where to poke a hole and still avoid touching the metal elements, but it’s a little harder with a black antenna. If you do choose to mount the antenna outside, and especially if you’re poking holes in it, you have to know you’re voiding the warranty but hey, it’s your antenna… you do what you want with it. It’s a free country.

You probably need to know that you’ll be replacing that antenna a lot more often if it’s subjected to the elements, but there’s a little bit of risk in everything, right?

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.