Why does anyone broadcast on VHF-Low? (And why is it such a problem?)

Folks, I’ll admit that this isn’t an article I thought I’d be writing in 2022. Certainly I didn’t expect to be talking about this fifteen years after television transitioned from analog to digital. Remember those days, back in 2007-2009? You probably bought your first flat TV back then, because digital TV allowed for HD picture that was better than you’d ever seen. Even if you didn’t use a TV antenna then (or now), it was the over-the-air broadcasting transition that really drove that tech. So, let’s talk about that tech, and why it’s still the way it is.

Understanding frequency ranges

When it comes to TV reception, there are actually three different sets of frequencies in use. If you’re familiar at all with over-the-air TV, you’ve heard of VHF and UHF. That’s how they’ve been presented. The VHF range is thought of as channels 2-13, while the UHF range (as we use it today) is channels 14-36. But there’s a little more to it than that.

Between channels 6 and 7 are a chunk of frequencies that are used for things like FM radio. So it’s really better to think of VHF-Low (channels 2-6) and VHF-High (channels 7-13.) It doesn’t really make a difference in the way you use your TV, but it makes a big difference in the way antennas are built.

The dirty little secret of antenna design

Folks, this is just basic physics. We measure “TV channels” as a range of frequencies. Lower numbered channels have lower frequencies. Channel 2 is at 54-60MHz, while channel 36 is at 602-608MHz. And if you have a TV antenna, you should care about that.

There’s a relationship between frequency and antenna size, and it’s pretty simple.

The frequency of a signal, to put it simply, is how many waves are broadcast in one second. The wavelength of a signal is, to put it just as simply, the size of one wave. As you put more waves in the same period of time, the waves have to get shorter. So there’s a fixed relationship between frequency and wavelength. The wavelength of channel 2 is about 5.55 meters. The wavelength of channel 36 is about .5 meters. As you go up in channel number, the waves get shorter.

And here’s why you should care about that

Here’s the definition of an antenna that I want to use. An antenna is a piece of metal that is the right size to start vibrating when a wave of a specific size hits it. (I know there’s some inaccuracy to that, but this is a useful definition anyway.) In order for the antenna to work, it has to be very close to an even fraction of the size of the wave. Let’s say your wave is 4 meters wide. That would mean it’s channel 5, by the way. The ideal antenna for this frequency would be 4 meters wide. That’s over 12 feet, by the way, and that’s kinda too big for most homes. So you use an even fraction like 2 meters or 1 meter. Those work pretty well too.

And what that means is…

…that you need a big antenna to get those low-numbered channels. The problem is that people don’t want big antennas. So, antennas are sold as UHF-only, UHF/VHF-High, or UHF/VHF-High/VHF-Low. That way people who don’t need those low-numbered channels can get a compact antenna that suits them.

Why would ANYONE need an antenna for VHF-Low?

Like a lot of other people, I thought that VHF broadcasting, especially VHF-Low, would be gone by now. One of the goals for the digital transition was to move as many stations as possible to UHF so that people could use smaller antennas. However, a small number of station owners just didn’t want to change their frequencies. The government tried throwing money at them, but they just wouldn’t do it. So, there are some areas where you have channels 2-6 being used. (Here’s a recent list.) Most of those stations are low-power repeaters or appeal to narrow markets. But a few, like Philadelphia’s channel 6, are network affiliates.

I can’t say I understand the logic. There’s a system called PSIP that translates the real broadcast frequencies into different channel numbers. That way you could broadcast on channel 25 and still have people tune their TVs to channel 4 just like they always did.

Still, some station owners just refuse to make the move. Others have actually moved back to VHF because the UHF frequency range got too crowded. It’s also somewhat less expensive to broadcast on VHF because it takes more energy to make higher-frequency signals. So for some, I’m sure it came down to money.

Here’s what you can do

The best thing to do is to get the facts before you buy an antenna. You can get a professional recommendation from a real antenna tech, for free. Just fill out this form. If you have questions, call us at 888-233-7563 during East Coast business hours. We’re ready to help. When you’re ready to buy, I hope you consider the great selection of antennas at SolidSignal.

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.