Prior Restraint
Early radio receivers took advantage of the technologies available and assigned each transmitter a unique frequency. It is a very inefficient approach and required a complex regulatory system to keep all the signals sorted out. Since World War II we've had the ability to use signaling approaches that are far more effective and do not need this regulatory regimen. Yet we still cling to spectrum allocation and the censorship inherent in the onerous regulatory system
22-Jan-2003Version 2: 2023-03-18 10:09:41

The Legacy of the Spectrum: Communications Policy as Censorship

For a more technical view of the spectrum policy you should read Open Spectrum FAQ. Reading it made me wonder why it is necessary to make a case for "Open Spectrum". That seems backwards�

Update: After writing this essay, David Reed sent me a pointer to an essay by Yochai Benkler and Larry Lessig posted by the New Republic: Will technology make CBS unconstitutional? After reading this essay and the one in The New Republic you should should come away wondering why we are so willing to accept censorship, no matter how well-intentioned, without any attempt to prove that such prior restraint is necessary.

A drunk is crawling on the ground looking for his car key, the passerby offers to help and asks where to start looking and the drunk points to the other end of the block. When the passerby asks why he's looking under the lamp, he says "that's where the light is". This is an old story. You can tell by the word "drunk" and the idea that anyone would help such a person find his car key. But it isn't as old as the idea of spectrum allocation which is today's street lamp, familiar but it is a kind of misdirection.

The idea of free speech is still viewed with extreme skepticism. The tendency is to assume the worst and try to preempt it. The framers of the US Constitution were amazingly foresighted and courageous in shifting the burden of proof to those who wished to restrict free speech and in disallowing prior restraint. Yet we have imposed the most egregious and unnecessary form of prior restraint when using technology to carry our voice. Communication is, in effect, a synonym for speech. The Federal Communications Commission's job is to regulate speech.

It's as if we were having a party and someone came into the room and told everyone to be quiet and gave out pieces of paper with a time and a place telling each person when and where they could talk. If there were a possibility young people would overhear you couldn't use certain words even if there were no other venues and even if you felt the language was appropriate for them.

Put that way it seems outrageous. Yet if we communicate using radio waves instead of sound waves that is precisely what the FCC is doing.


Because in the 1800's people observed that if you have tuning forks and hit one, any other nearby tuning fork of the same kind would start vibrating along with the first and the others would stay still. The rate of vibration is called the frequency -- it's the English word for "how often" the fork vibrates. It seemed like the perfect solution for the important problem of sending two signals on the same telegraph wire at the same time. Alexander Graham Bell was working on this problem but was more successful with this unauthorized side-project -- the telephone -- which made us forget about the telegraph problem. With the telephone you could listen to music and hear the individual instruments even though they shared the same wire!

The idea of the harmonic telegraph (as it was called) was rediscovered and as the solution to the problem of how to distinguish between two signals sent over radio waves. The electronic tuning forks worked far better than the physical ones.

It worked so well that the word "radio" become synonymous with the "oscillator" and this expedient solution become deeply embedded within the psyche of the radio engineer. In fact, the premier general interest publication from the IEEE (formerly the IRE -- the Institute of Radio Engineers) is called Spectrum. And every time you ask about radios, the question is automatically translated into a question about electronic tuning forks.

This is the way language works, the assumptions become invisible and thus unquestioned. This can be very confusing. At the consumer electronic show last year I wanted to find the electronics for low power transceivers. A transceiver is a radio but whenever I asked about radios, the response assumed I was asking about radio broadcasts. The popular meaning of "radio" is "broadcast industry" and the industry is organized around positions on the spectrum dial (the tuner). In Television (pictures over "radio") we assign channel numbers to these frequencies. All of the creative content is herded into narrow channels. These channels are owned by a small number of gate keepers and their scarcity makes them expensive and thus only content of general interest can be justified.

Since radio has become identified with spectrum allocation and as a medium for entertainment it is hard to revisit the underlying principles. Many of those most involved in using these technologies have internalized these assumptions. This is especially true for those who are not deeply technical and lack the language to talk about radio except as a channeled entertainment medium with a few "bands" allocated for special purposes. The tuning fork is the landscape.

Yet when we take these same technical people and ask them to solve a very different problem they aren't limited in their thinking.

In the 1960's NASA sent the Voyager probe to Jupiter but would allow only 25 Watts for the radio. In order to listen to this faint signal from billions of miles away despite the background radiation from Jupiter that was, perhaps, trillions of times as powerful, they used a technique developed during Word War II -- the shaped wave form. By spreading the signal over a portion of the spectrum (hence the term, spread spectrum) they were able to create a unique shape that acts like a key. If you have the corresponding receiver you will see the signal. If you don't you may not see any signal at all.

In a sense the you are spreading your bet over many frequencies so the signal is more likely to get through and since the number of such shapes is essentially unlimited, so are the number of different signals that can coexist. To learn more you can go to To be technically precise the term spread spectrum is used for both shaped waves and for signals that hop over discrete frequencies.

By contrast, a signal sent at a single frequency is very vulnerable. The vulnerability is understood.

When we have two solutions to a problem and one works very badly and the other works very well the obvious response is to use the better solution.

The problems with the weaker solution were recognized from the beginning and, at that time, the lack of a more effective alternative lead to the creation of rules that to limit the number of signals so each one would heard by a matching, though imprecise, oscillator.

Spread spectrum technologies were originally developed to hide signals during World War II so it isn't surprising that few saw it as applicable to everyday radio. It took a half century for it to be used as the basis for the CDMA cellular phones.

The spectrum had already become so identified with "radio" that the limitations were accepted as necessary. Instead of seeing the limitations and problems as symptomatic of the underlying flaws, more rules and regulations were added to keep the system from falling apart. The limitations on free speech were recognized and rules were created to try to create synthetic free speech with laws to provide "equal access" and limitations on how many frequencies a single entity could own!

The presumption that underlies the FCC management of communications is that we must have prior restraint because we are not allowed to do better than the methods used over 100 years ago! Communicating with a radio is treated as being special and not only is prior restraint allowed, it is required!

Rather than putting the onus on those who claim harm, the onus is put on those who wish to have a voice. They must prove they will not only do no harm, but also that they will not annoy or interfere with others no matter how naive the affected system is.

The standard is based on the most naive technology. It's no different from requiring that automobiles be designed so as not to interfere in anyway with horse traffic.

David Reed has looked at the current technical assumption in great detail and radios simply do not have to act just like tuning forks. You can simulate tuning forks and create concepts like interference but that isn't a sound basis for a public policy. It imposes severe prior restraint on the ability to communicate and denies us the economic benefit of the medium.

The Internet has given us proof that we do not need such a tightly managed medium in order to communicate. In fact, we communicate far better without it. Congress has mandated that in 2007 we will have to convert all of our televisions to so-called HDTV. Yet the "high" in HDTV is much worse than any computer screen in use today. The problem is that the concept of spectrum has created an artificial scarcity and we have to have everyone change at once in order to repurpose this artificial channel.

Yet, with the Internet, there is no such scarcity because we don't herd all communications into limited and narrow channels. In fact HDTV (and much high quality) can simply be provided now without waiting. Well, almost � the FCC is also maintaining a similar scarcity on the wires between our homes and the rest of the Internet. The reason we have such limited connectivity is purely due to policies. The technology to provide much high speed connectivity is readily available.

This dual scarcity is totally artificial yet it has created a barrier to economic growth. The growth curves presumed an abundance of connectivity that would allow us to innovate in how we communicate and what we communicate. But this dual scarcity has sabotaged this growth.

Just as the word "radio'" is heard as "spectrum", we have confused the concept of communicating with the medium over which we communicate. The presumption that we must regulate the medium gives license to regulate communications.

Yet this extraordinary exception to free speech is accepted without question. One might one be skeptical of the idea that we do not need spectrum allocation. But at very least the courts must demand that those imposing such stifling and complete and arbitrary prior restraint establish an overwhelming reason that they must do so.

Having accepted this unwarranted limitation on free speech it should be surprising that the FBI and other agencies view it as their right to listen in on our communications and view those who thwart such intrusions with suspicion. The Communications Assistance for Law Enforcement Act of 1994 makes it the duty of telecommunications carriers to cooperate in the interception of communications for Law Enforcement, and for other purposes! (

There is an effort to extend this reach into the hearts of our computers within our homes (considered sacred in the US Constitution) and to attempt to ban the use of encryption! It is as if the post office required that we put postage on each email message and the police made it illegal to lock our front doors!

Free speech gave us the ability to innovate without having to first justify ourselves to the King and it was a major factor in the shift of economic growth from Europe to the United States. Unfortunately we are in a world wide dark age with spectrum allocation being used to deny us the ability to amplify our voices with simple technology.

We must recognize that connectivity, be it by radio or wire, is not inherently scarce. Until we demand an end to this artificial scarcity it will be difficult to restart the economic growth of the last decade which was built upon the newly found freedom to connect. This is not just an issue in the United States. Our movement towards global connectivity has been challenged.

The concept is far too important to be held back as we find ways to work around the limitations. But as long as we deny ourselves abundance our economy will be moribund.