Home-Built Radio Rules

The FCC's treatment of home-built devices could stand an update

3 min read

As a youngster, I loved reading about home-brewed electronic projects. One, I recall distinctly, was ”a tuna-can radio,” a low-power transmitter that could be put in a package no bigger than 5 ounces of albacore.

I thought about that circuit again decades later when I came across something called a cantenna. Another mashup of radio and recycling, this homemade Wi-Fi antenna can supposedly boost your wireless range. A little research revealed other antenna configurations that promised even better results, including those of the FabFi collaboration in Afghanistan, which uses ”common building materials and off-the-shelf electronics to transmit wireless Ethernet signals across distances of up to several miles,” according to the Jalalabad FabLab’s Web site.

With that for inspiration, I set about to rig my own high-gain antenna. My ambition was to access the Internet through my community’s downtown wireless network, which is about 400 meters from my house.

It would be a fine DIY project, I thought, for this magazine’s Hands On column. I was wrong. The reason: Federal Communications Commission regulations forbid what I intended to do—despite the fact that high-gain antennas designed to extend the range of Wi-Fi equipment are sold throughout the United States. You can buy these antennas from such ubiquitous U.S.-based retailers as Walmart and Office Depot, for example. This puzzling situation reveals some interesting things, both about the FCC’s legal authority to police the airwaves and about its ability to keep up with the pace of technological advance. Let me explain.

One of the relevant regulations—Part 15, section 15.23(a)—seemed to give people like me a pass to hack such equipment together, so long as ”good engineering practices” were used. The problem was that another section, 15.204(c), says, ”[A transmitter] may be operated only with the antenna with which it is authorized.” Confused? I was too. So I sought clarification from the FCC.

Rashmi Doshi, chief of the laboratory division of the FCC’s Office of Engineering and Technology, patiently answered my questions, citing specific entries in the FCC’s knowledge database. He explained that the regulation on home-built devices applied only to things that were built from scratch, not to modifications of FCC-certified radio equipment.

So the rules wouldn’t, in fact, allow me to build and use the antenna I had envisioned. But why, then, could I easily purchase high-gain add-on antennas for Wi-Fi equipment? Doshi explained: ”We do not regulate antennas by themselves, as they do not generate RF signals. Accordingly, the sale of any antenna, including a high-gain antenna, is not illegal. However, it is illegal to use a high-gain antenna with a transmitter which it is not approved for.” Captain Renault’s famous line from Casablanca—”I’m shocked, shocked, to find that there’s gambling going on here!”—echoed in my brain.

In fairness to the FCC, it may not have the legal authority to outlaw the sale of such antennas. What’s more troubling to me is the FCC’s interpretation of the regulation intended to deal with home-built equipment. That seems as antiquated as a tuna-can transmitter.

After all, these days radio hackers—like those involved with FabFi—are doing extraordinarily interesting things. But most of these experimenters are building on the shoulders, and circuits, of other do-it-yourselfers, open-source communities, and, yes, equipment manufacturers. Few people are still soldering transistors together one by one. Instead, they are modifying commercial equipment or building new gear using existing RF boards or modules. The definition of ”scratch built” is thus quite murky.

Why not foster this creative energy by including all of it under the label ”home built”? The danger, I suppose, is that it opens a door for an unscrupulous vendor to bypass FCC rules by selling boxes that anyone could plug together and call home built. Perhaps the FCC just needs to define a home-built device as something requiring skills beyond those of the typical consumer. In an era when policymakers struggle to figure out how to boost young people’s technical know-how, the FCC should somehow recognize—and even embrace—the way today’s tinkerers work.

This article originally appeared in print as "Radio Daze."

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