On February 17, 2009, analog television signals—the mode of TV delivery since the 1940s—will be completely replaced by digital. Here are the basics behind this monumental change, and what it means for TV viewers.

Digital vs. Analog

Simply put, a digital signal is an improvement over analog. Analog signals are susceptible to interference or “noise.” Digital signals are more efficient, providing better picture and sound, and the opportunity to broadcast multiple content streams.

Big Broadcast Changes

How dramatic is the digital transition? Eighteen broadcast channels—52 through 69 on the UHF band—will no longer exist. Since digital delivery frees up space, TV broadcasts along those frequencies will be discontinued. Roughly 145 stations in the US currently use those channels, and nearly all will continue on digital channels. (read more)