If you use an antenna that’s twice as big, do things come in twice as well?

This question actually comes from our YouTube channel, where you can find new content every week. It’s a great place to get caught up with what’s going on with Solid Signal, get questions answered, and get to know all about how generally cranky I am.

A viewer asked if he could improve reception by creating an antenna that looked just like one of our antennas but was twice as big. The answer is actually a little more complex than you think.

Generally speaking, no.

Antennas are designed to pull in specific frequencies. The size of the antenna is directly tied to the size of the wave it’s trying to catch. Higher frequencies have shorter waves, which is why your cell phone doesn’t need an antenna like the one on your roof.

Traditionally, TV antennas are exactly the size they need to be. The antenna itself is half the size of the frequency it receives. This is called a “half-wave” dipole. This is the most efficient antenna because it combines the smallest effective size with very good reception.

If you take a half-wave dipole and double it in size, you have a “full-wave” dipole, something practically no one talks about. A full-wave dipole is really only a little more effective than a half-wave one and it’s bigger and more expensive. It’s not worth it.

The most important problem with a full-wave dipole, though, is that it picks up frequencies you don’t want very well. If you’re using a  dipole for 180MHz, it’s also picking up 90MHz and 360MHz. Engineers are aware of this and frequency plans are staggered so that interference doesn’t happen. But, if you use a full-wave dipole, you’re actually picking up those other frequencies quite a bit better and that can be a problem.

Except, there’s a loophole.

Smaller antennas tend to use what’s called a “quarter-wave” dipole. This is an antenna that is one-quarter the size of the frequency it wants to receive. Although it’s not as effective it is smaller. That’s why quarter-wave dipoles are used in indoor antennas.

In this case, doubling the size of the antenna actually would give you a half-wave dipole which would generally mean better reception. You’d have to fashion the antenna carefully and it would be a challenge keeping it indoors, though. Which brings up the real question:

Why wouldn’t you just get the right antenna in the first place?

It seems like an awful lot of work to re-engineer an antenna just to make it work worse potentially. With so many antennas to choose from in Solid Signal’s excellent catalog, you can get the antenna you need. You don’t have to invent it. Luckily we can help you figure out which antenna that is, with the help of our free antenna request form. Fill it out and a real, honest, certified antenna tech will review it and get you the answer you need. We’ll even include suggested parts and accessories. This isn’t just some app making arbitrary decisions, this is a real person who knows what they are doing.

Why not give it a try, instead of trying to create some gigantic duplicate of an antenna that already exists? What do you have to lose?

 

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 6,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.