Broadband, wideband, narrowband: What’s the difference?
In the Internet space, broadband is good. It’s a catch-all term for services with faster speeds. It’s where we all want to be, particularly those of us who remember dial-up modems. Having broadband means faster downloads of content for your smartphone, computer, Internet-enabled TV or content-streaming device. Your devices are either broadband-enabled or they aren’t.
Engineers argue about what download or upload speeds constitute broadband, e.g., over 2 Mbps (megabits per second). Most consumers don’t know — and don’t care — about how to measure a megabit but do know they have broadband if they can watch a movie or video clip on an Internet-enabled device without it stalling (buffering, if you prefer a more accurate term). The opposite of Internet broadband would be called narrowband, but that’s only a term used now to distinguish what we had in the “old” days, now that we have broadband. Another way of thinking about broadband is to envision a stream of running water: A faster stream carries a floating boat more quickly.
For two-way radios — technically called land mobile radios by the Federal Communications Commission — there’s another technology transition going on. However, the attractiveness of “bands” is not intuitive based on the prior broadband and narrowband comparison: in this context, “narrowband” is better, and “wideband” not so. Radios for many years were wideband, meaning they utilized more spectrum, e.g., 25 kHz (kilohertz) and even up to 50 kHz in the distant past. Using the stream of water analogy above, wideband would refer to the width of the stream, i.e., you can fit more boats side-by-side in the water.
The reason why narrowband is better is that technology has improved over the years, driven largely by a conversion from analog to digital, allowing voice and data communications over two way radio frequencies to consume less bandwidth, essentially allowing the same or better communications to take place over half the spectrum. The FCC mandated years ago that radio users in the 150–174 MHz and 421–470 MHz bands convert to 12.5 kHz “narrowband” channels (and equivalents) for their communications by Jan. 1, 2013. Manufacturers have continued to improve the efficiency of their radios, so even 6.25 kHz narrowband radios exist today, performing the same and better functions that older wideband radios did.
So, for two-way radio usage, narrowband spectrum is good. For Internet usage, narrowband speeds are bad. In a future Wireless Connections article we will review strategies that some land-mobile-radio operators are considering to use broadband applications over narrowband frequencies. Nothing ever stays the same. That’s a good thing!