There’s a new trend in antennas. It comes from the idea that an omni antenna might not cut it in every situation. In the last several years, many broadcasters have moved back to VHF broadcasts. This means a larger antenna is needed and it means that omni antennas don’t work as well.
Let’s back up a little bit
What is an omni antenna?
Omnidirectional, or omni, antennas, pick up signals from all directions at the same time. They are usually round like this Antop UFO antenna. With advances in low-noise amplifiers, they’re more useful than ever at picking up distant signals. But the fact is that the antenna elements themselves are simply too small to pick up VHF signals efficiently.
Why are VHF signals a problem?
Every broadcast frequency has its own wavelength. As the frequency goes up, the waves get smaller. VHF frequencies from 54-210MHz have waves measured in feet. For example, the broadcast waves from channel 7 are about 6 feet long. In general, an antenna should be half or one-quarter the width of the signal it’s trying to pull in. So, this omni antenna isn’t going to do a lot.
The answer from several manufacturers has been to add VHF capability through a dipole antenna that extends beyond the main antenna. For example, our friends at Televes did this when they made the excellent Dinova antenna.
The VHF antenna extends from the main antenna and gives a lot more capability. We’ve also seen this same technique applied to omni antennas, for example this model from Lava.
This omni antenna has two elements extending out from it. These give this relatively small antenna a lot more power to pick up VHF signals, as long as you aim it properly.
How to aim
The overall antenna is going to pick up signals from any direction. However, you’ll only get VHF signals from a small range at the front and back. Overall, the antenna will pick up VHF signals from about 1/4 of the sky, and the other 3/4 of the signals won’t come in well.
So, the key is aiming. The antenna should be pointed so that the VHF elements are perpendicular to the towers they are pointed at. You can use a site like TVFool.com or an app like this one from Winegard to figure out where your signals are coming from. Remember you need to know the actual broadcast channel, which is often different from what you think it is.
The antenna should be aimed so the VHF elements are completely visible to the towers. It’s easier to show that in a picture.
Imagine you’re standing behind the antenna in the photo and you’re looking at the broadcast towers. The antenna would look something like this:
Sorry for the simple drawing but I think it conveys the basics. You can see the wide elements at the left and right.
Choosing an antenna
It’s not easy to choose an antenna. In fact, with hundreds to choose from it can be downright difficult.
If you need help choosing, fill out this form for a free recommendation from an expert. Our techs don’t use an app, they do it the old fashioned way by looking at everything in your form and actually thinking. It’s worth a try!