How often should you rescan for channels if you have a TV antenna?

Ask 10 people, you’ll get 12 answers. The best answer is, of course, when it needs it, but who has the time to research FCC filings and check websites just to figure out when one of your local channels has added a subchannel or changed frequency allocations? Most of us simply aren’t that committed to the process.

The whole idea of scanning for channels originated in the 1980s when TVs with computerized tuners became common. Some TVs had 10-15 buttons that could each be set for a channel, but as time wore on it became more common to have a TV with a digital readout for the channel. A process called “channel scanning” would automatically eliminate channels with no content, making it possible to flip from channel to channel without a bunch of static in the middle, and stopping moms everywhere from saying “slow down, you’ll break the knob!”

That idea — going from channel to channel without static in-between — sounds pretty simple today but believe it or not, it was revolutionary back in the days of Wham! and Madonna. It was a selling point, a gateway to some very expensive TVs.

In those days, though, you usually scanned for channels once, or at most, you scanned every time you moved from city to city. That’s how things stayed until the late 2000s when things got ever more complicated. Because broadcasters needed to maintain both their analog (old-school) and digital (HD) channels, they had two different frequencies. And, you better bet that stations that were used to advertising themselves as channels, 2, 4, 5, or 7 weren’t going to change their plans and call themselves channel 36. That wasn’t happening. So, the government implemented a system called PSIP which lets people enter in one channel while the TV tunes to another. You may think you’re going to channel 2, but really the actual frequency could be channel 48. You’d never know.

That worked out for everyone because no one had to try to remember how to find their favorite channels, but it created another extra step. Instead of scanning for channels once, in the early days of HDTV some people found they needed to scan every month or so. Scanning for channels didn’t just eliminate the static, it rebuilt the conversion list in your TV so you could tune to the channel number you knew and get what you wanted.

Slowly, things have gotten more and more stable, and for the most part it isn’t necessary to scan for channels more than about once every three months, if that. But of course, that’s going to change. Sometime in the next 18 months, the FCC plans to “repack” the broadcast spectrum, moving channels closer to each other and taking away a bunch of broadcast frequencies so they can be used for cell phone data instead. This is a good deal for everyone, but it means that you may need to scan for channels a little more often as the transition is happening.

If you don’t rescan for channels, you’ll start losing them. You’ll go to tune to your favorite and you’ll get nothing but static. Of course they’ll probably tell you a couple of months in advance, and you can always fix things with a simple channel scan. While it’s different on every TV, it usually begins with pressing the {MENU} button on your TV remote and looking for something that says “Setup” or “Antenna Setup.” Wander through the menus until you find “Channel Scan” and … do it.

So what’s the bottom line here? As a matter of course I scan for channels every 3 months, and lately it hasn’t made a lot of difference. It’s just one of those maintenance tasks like changing the furnace filter or cleaning the gutters. It doesn’t take a lot of time but if you don’t do it, it could be a problem after a while.