# Why couldn't the FCC allow other uses of bandwidth so long as they don't interfere? **URL:** \ **Category:** Factual Questions\ **Created:** [March 21, 2008, 1:14am UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170 "2008-03-21T01:14:46Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [March 21, 2008, 1:14am UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/1 "2008-03-21T01:14:46Z")
The FCC prohibits unlicensed uses of the airwaves, partly to enforce a [small group’s version of morality](http://www.sourcewatch.org/index.php?title=Parents_Television_Council#Indecency_Complaints) but largely to make sure the airwaves don’t degenerate into random noise and Clear Channel broadcasts. They do this by slicing up the full spectrum into bands, and allocating those bands to specific uses. It is illegal to use a band for anything other than its allocated purpose. This makes sense in dense regions, where pretty much every available frequency is in use by someone. Out here, on the other hand, most of the dial is completely empty (AM, FM, analog TV, and so on are all mostly quiet) and could be used for anything at all if you didn’t fear the FCC [party-vanning](http://wikichan.org/index.php/4chan_Party_Van) you and your gear. How come the FCC doesn’t allow _non-interfering_ uses of bands that would otherwise go unused in a given area? This is (technically) orthogonal to the concept of licensing: The license _could_ cover the mere usage of a broadcast rig on any frequency and allow such usage as long as the Prime Directive (the principle of non-interference) was strictly adhered to. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [March 21, 2008, 3:05am UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/2 "2008-03-21T03:05:30Z")
They do. There’s a band called ISM (industrial, scientific, medical) which is unlicensed and allows pretty much any type of operation (within the power restrictions). The hitch is that you must accept interference from any other device. There are all sorts of wireless devices operating in this band. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [March 21, 2008, 3:44am UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/3 "2008-03-21T03:44:48Z")
[QUOTE=beowulff] There’s a band called ISM (industrial, scientific, medical) which is unlicensed and allows pretty much any type of operation (within the power restrictions). [/QUOTE] This isn’t what I asked about. It’s somewhat close, though. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [March 21, 2008, 12:03pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/4 "2008-03-21T12:03:01Z")
Derleth asks why other bands can’t be used by non-interfering transmitters, not why there isn’t a band like ISM, right? I would guess the reason is that it would be impractical to announce that non-interfering use is allowed, and then spend lots of resources settling arguments about what constitutes interference and who has to stop doing what. Interference can take a lot of resources to track down. People driving around making measurements, almost finding the source but then it turns off, etc etc. Also, HAMs will no doubt agree that it is possible to transmit properly in an allowed band, and still get complaints from neighbors, for example because the neighbor’s television set is too sensitive to what it should be seeing as out-of-(TV)band noninterference. The more transmitters there are, the more work this all entails. There’s another practical side. If it’s legal to use, say, a wireless thermometer in Montana that transmits within the FM Broadcast band, when a consumer in Montana moves to New Jersey and hangs their thermometer up, trouble ensues. So, no doubt the FCC would cringe at the idea of mass-produced products whose proper use requires the user make a judgement about the potential for interference. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [March 21, 2008, 12:06pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/5 "2008-03-21T12:06:38Z")
I’ll add that some portions of the Ham radio allocations are shared. Particularly the 70CM band where the Hams are secondary users in some areas of the USA. In the HF section, ITU Region 1 SW broadcasters populate the lower parts of some bands. But since they use AM and we use sideband it’s not a problem. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [March 21, 2008, 12:39pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/6 "2008-03-21T12:39:05Z")
[QUOTE=Derleth] The FCC prohibits unlicensed uses of the airwaves, partly to enforce a [small group’s version of morality](http://www.sourcewatch.org/index.php?title=Parents_Television_Council#Indecency_Complaints) [/QUOTE] Your cite is somewhat lacking: very few of those complaints were upheld. Just because they complain a lot doesn’t mean that the complaints are given any credence. For instace, [this site](http://www.techliberation.com/archives/038997.php) says > [@Techliberation.com](#): > > The WSJ filed a FOIA request to examine the complaints for that program and found that “all but three appeared to originate as computer-generated form letters (from the PTC).” In other words, virtually every complaint was identical and originated with the PTC’s website. “Only 2% of the people who filed complaints, or about 135, added personal comments,” Schatz found. The WSJ article requires a subscription. For instance, the [FCC obscenity site](http://www.fcc.gov/eb/oip/) says they only took action in 12 cases in 2004, despite 1.4M complaints. > [@FCC](#): > > The FCC vigorously enforces this law where we find violations. In 2004 alone, the FCC took action in 12 cases … At the same time, however, the Commission is careful of First Amendment protections and the prohibitions on censorship and interference with broadcasters’ freedom of speech. The FCC has denied complaints in cases in which we determined the broadcast was not indecent based on the overall context of the programming. And in 2005, none of the 233K complaints were upheld. [PDF of stats here](http://www.fcc.gov/eb/oip/ComplStatChart.pdf). ---
**Author:** ![nd\_n8](https://avatars.discourse-cdn.com/v4/letter/n/439d5e/32.png) [@nd\_n8](https://boards.straightdope.com/u/nd_n8)\ **Post date:** [March 21, 2008, 1:03pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/7 "2008-03-21T13:03:01Z")
[QUOTE=beowulff] They do. There’s a band called ISM (industrial, scientific, medical) which is unlicensed and allows pretty much any type of operation (within the power restrictions). The hitch is that you must accept interference from any other device. There are all sorts of wireless devices operating in this band. [/QUOTE] From my experience with the ISM band, not only do you have to accept any interference but have to register the range (modulation?) when you apply for the liscense. Violations come with considerable fines. Even so, with the frequency and range set within limitations on the radios at our parent plant, we still get signal on our maintenance crew’s radios when they come to my warehouse 1.7 miles away (dense inner city and industrial environment with a major interstate running through the middle). Perhaps the FCC limits use of non-specified bands in rural areas because, no matter how tight the regulations or how dedicated the effort to conform to these regulations, sometimes signals pass through and could wind up in an area where that band is assigned. Just a theory based on limited experience though, I could be quite wrong. ---
**Author:** ![mks57](https://avatars.discourse-cdn.com/v4/letter/m/b9bd4f/32.png) [@mks57](https://boards.straightdope.com/u/mks57)\ **Post date:** [March 21, 2008, 1:23pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/8 "2008-03-21T13:23:07Z")
Just because you think that you aren’t interfering with anyone, doesn’t make it so. Not hearing anything on a specific frequency with a particular receiver and antenna does not guarantee that you can transmit on that frequency without causing interference. ---
**Author:** ![BJMoose](https://avatars.discourse-cdn.com/v4/letter/b/5fc32e/32.png) [@BJMoose](https://boards.straightdope.com/u/BJMoose)\ **Post date:** [March 21, 2008, 3:44pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/9 "2008-03-21T15:44:17Z")
[QUOTE=mks57] Just because you think that you aren’t interfering with anyone, doesn’t make it so. Not hearing anything on a specific frequency with a particular receiver and antenna does not guarantee that you can transmit on that frequency without causing interference. [/QUOTE] Bingo. The harmonics of your signal could interfere with transmitters on certain other frequencies; your signal and someone else’s might combine in a third party’s receiver (intermodulation) and make that frequency unusable. Problems like this are why UHV TV channel assignments were so scattered - in any given area just a handful of channels could be used without causing interference on other channels. ---
**Author:** ![Will\_Repair](https://avatars.discourse-cdn.com/v4/letter/w/a698b9/32.png) [@Will\_Repair](https://boards.straightdope.com/u/Will_Repair)\ **Post date:** [March 21, 2008, 4:35pm UTC](https://boards.straightdope.com/t/why-couldnt-the-fcc-allow-other-uses-of-bandwidth-so-long-as-they-dont-interfere/442170/10 "2008-03-21T16:35:09Z")
[Footnote on clear channels](http://www.ac6v.com/clearam.htm) : > [@](#): > > Clear channel stations used to be “clear” but beginning in the early 1980s, additional stations were authorized to operate on clear channel frequencies at night, often with greatly reduced power and directional antennas Clear channel stations can use 50,000 watts of power and many use non-directional antennas. In the early days of radio, no other stations could operate on a clear channel station’s frequency between sunset and sunrise. Clear channel stations could be heard over much of the country at night. While the “breaking up” of clear channels may have been economically necessary for daytime-only stations, it did result in many clear channel frequencies sounding much like regional channels at night. Now a days some of the big 50KW night stations have directional antennas and this results in a null in certain directions so as not to interfere with other biggies. Some AMs are non-directional daytime and go directional at night to protect other stations via skywave, but there are variations on this theme. Some stations even increase power at night! [Table of clear channels.](http://www.csgnetwork.com/amclearradiotable.html)