Waves Of Interference

How the CB radio created an interference problem for television sets

Radio interference has long been a long, unusual annoyance in our society, appearing in all sorts of unusual places. Case in point: In the late 1940s, a church in Spokane, Washington found itself annoying local residents when its chime somehow kicked the radio onto the loudspeakers—ensuring the locals they might be getting some Spike Jones recordings along with their 6 a.m. bell chimes.

At the time, the incident was a strange oddity—after all, we didn’t have that many radio devices in our homes. But gradually, things started to shift, and it started to become more of a problem as TV sets, ham radio operators, radar systems, and other radio-driven devices started to compete for the same finite frequencies. Hell, even noisy power lines could cause issues, as the Amateur Radio Relay League could tell you.

This was especially a pain during the early era of home electronics, as it created challenges for capturing TV channels, and high-end stereos could gain some unwanted fuzz that didn’t appear on the original album. An August 1962 edition of Popular Science had a whole feature dedicated to giving readers advice on how to get rid of ghosting, channel interference, and other issues that were common parts of the TV experience at the time. “Close observation of the symptoms on your screen is the first step,” writer Art Margolis explained.

As a 1961 article on RF’s impact on hi-fi stereo systems noted that the issue was both diverse and complex in nature:

Interference from radio stations, amateur radio operations, TV and X-ray generally manifests itself as a buzz, hum or high-frequency squeal. In some cases that involve broadcasting, voices come blasting through the speakers of high fidelity systems.

External switching transients from appliances inside the house manifest themselves as pops when appliances are turned on or off. This type of interference can often be corrected at the source with a commercial AC line filter.

But more esoteric types of interference can’t be corrected as easily.

One of those esoteric types turned out to be CB radio. Made available in the 1940s on a publicly accessible radio band and gradually tweaked over time, it was initially cost-prohibitive for average consumers, making it a popular option for small businesses or niche interests like boating. But the appeal of the concept was hard to ignore. As a 1960 Popular Mechanics piece put it:

To get on the air on the Citizens Band, you don’t have to know a thing about radio. There are no operator’s licenses or technical examinations. All you do is buy the equipment, send for a station license (a mere formality, though a necessary one) and you’re all ready to operate.

However, that simplicity proved a double-edged sword. By the 1970s, the technology had begun to reach more consumers as the equipment dropped in price. The FCC tried to meet the demand by lowering the cost of licensing. However, the demand was gradually creating an untenable, near-unusable technology, which the success of 1975’s “Convoy” certainly did not help ease.

This TV report is an absolute trip. It’s forgotten just how popular CB radio was—probably because it was the Twitter of the 1970s.

People were flooding the CB’s 23 channels with constant chatter—and when the FCC expanded the number of channels to 40, radio manufacturers responded by cutting the prices of the 23-channel models, which accidentally made things even worse, as the above TV report highlights. If you were into CB radio in 1977, odds are you were in for a world of pain—with the oversaturation kind of ruining the whole thing long-term and likely facilitating the gradual shift to cellular phones.

Also left suffering as a result of this: TV viewers, who were seeing much more interference during this era as the CB fad overwhelmed the wireless airwaves. The FCC was dealing with tens of thousands of complaints about CB radios harming television signals, and it was becoming clear that the commission had to take these concerns seriously.

How bad was it? Of the complaints the agency received about TV interference, a whopping 83% were caused by CB radios, according to a December 1977 Associated Press story, which noted the popularity of CB radios that Christmas would only worsen the situation.

The FCC felt that the issue was so serious that the agency created an informational guide to help manage the issue, How to Identify & Resolve Radio-TV Interference Problems. The booklet made clear that if a neighbor complained about your use of a CB radio, you had to take it seriously, and even described how, if necessary, you could get help from a “Local Television Interference Committee.” (While not universal, these committees tended to come from the amateur radio operator community in a given area.)

All of this is to say that, thanks to the many, many headaches that CB radio was creating for the FCC, it only makes sense that the agency’s guard was up around other sources of RF interference. You know, like the computer.

Sucks to be a regulator.

When computers hit homes, the FCC’s RF interference concerns kicked into overdrive

At first, computers largely appeared in businesses and universities. They hadn’t quite hit the home just yet, though electronics that had computing elements—think Pong consoles and the like—were starting to make their presence known.

That meant that these devices, like every other type of electric device (even light bulbs), could be a new source of RF interference, and as the personal computer started to gain attention and popular uptake, the industry had to adapt. Stuff like the Altair’s accidental musicianship would not fly.

And so too, did the Federal Communications Commission, which asked the public in 1978 to help determine a plan of action for better managing RF interference, after getting flooded with complaints for years on end. An inquiry document implied that the FCC was considering its options for about regulating this technology. The organization implied that it may not be cost-effective or even necessary, and even floated a voluntary approach.

“Greater immunity will require more sophisticated design, additional components, and increased testing, all of which will increase equipment production cost. The magnitude of this increase will depend upon the immunity standards prescribed,” the commission wrote, adding that the public may still choose the cheaper, unshielded option if given the choice.

After spending time digging in, however, it’s clear the agency decided that they needed to take a harder line than the voluntary one posed. After all, computers were taking over the household, and so too were VCRs, video games, walkie-talkies, and all matter of electronic devices.

Of course, the computer industry was still very immature at this time, with devices like the Commodore PET, TRS-80, and Apple II still quite new, each representing early attempts at bringing personal computers to a large home market. We were a step beyond the pure hobbyist nerdery of the Altair but far from maturity. The FCC wanted to head off issues with these new devices before things went too far—and saw the dynamic around consumer devices as being distinctly different from commercial platforms.

By September 1979, the FCC was ready to weigh in, and it was worried about your neighbor’s TV experience above all else.

“We are most interested in protecting an individual who is receiving interference from his neighbor’s computer. To a lesser extent, we are concerned about devices in the same household,” the agency wrote in its rulemaking document, FCC 79-555. (The goal? To prevent interference so bad that it harmed the experience for someone in a completely different home.)

The document, which applied Part 15 regulations to computers for the first time, made clear that CB radio played a decisive factor in the final result. (Especially given the timing, which came mere months after the FCC highlighted the sheer scale of complaints it received.) The commission learned a lot from its more laissez-faire approach, which ultimately damaged the consumer experience.

“Unless the Commission acts expediously to head off the problem, we may be faced with an intolerable interference problem similar to CB interference problems of several years ago,” the commission continued.

This was not good news for all these technology startups in the budding computer industry. Suddenly, companies large and small had to share their new products—and presumably, their trade secrets—with the FCC in an attempt to ensure that the electronics were safe to sell.

This created major headaches, especially for companies that already had products on the market, which now had to stop producing RF interference on TV and radio frequencies altogether. As the magazine Kilobaud put it in 1981: “After three years of study, the FCC handed the microcomputer industry a mandate: Get rid of the RFI by January 1981, or close up shop.”

These standards meant additional testing—including the use of a spectrum analyzer and a dedicated testing site to ensure that equipment meets respectable radiation standards. And these standards could be quite confusing for manufacturers, even affecting things like upgradeability. Per Kilobaud’s Chris Brown and Eric Maloney, “As far as the FCC is concerned, an 8K CPU that has the potential of being upgraded to 16K is actually two different computers.”

Put simply, this put a huge testing onus on manufacturers, likely raising prices in the short term and leading to additional metal shielding as a band-aid to retrofit existing designs to fit the FCC’s regulations. Large manufacturers likely were already doing a lot of this on their own. The problem was that this put a lot of additional pressure on the makeshift startups that made the sector viable in the first place.

Manufacturers had to adapt. For example, Apple released newer iterations of the Apple II, such as the Apple II Plus and Apple IIe, to help improve the electromagnetic noise that the original created. (Which means, if you want a computer with no RF shielding because you desire to make music via radio interference, get the original Apple II.)

Apple had to take this stuff seriously, because the FCC was paying special attention to them. The company was specifically cited in the commission’s rulemaking as being aware of the problem as far back as 1976. And it got nailed at least once for noncompliance: On top of all the other challenges that the ill-fated Apple III faced, the machine had to be recalled and replaced with a new model because its RF shielding wasn’t good enough.

Ironically, the rules were way less strict for computers in office or industrial environments, which received a Class A regulation, than for consumer tech, which required the stricter Class B designation. After all, if the goal is to prevent radio interference, your Facts of Life-watching neighbor is going to have bigger issues than your spreadsheet-embracing co-worker.

All of this was a pain to manage, but you’ll be surprised to learn that, in the end, all this added regulation probably ended up making the computer industry better.