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Low Power FM Report Rejects Interference Concerns

akb writes "Back in 2000, Slashdot covered the Low Power Radio setback by Congress, detailing a law which gutted an FCC initiative that would have created thousands of Low Power FM radio stations (LPFMs). Congress overruled the FCC, ostensibly because of interference concerns, and cut the number of stations from thousands to a few hundred, with hardly any in urban areas. A concession was made to allow a study of the interference caused by LPFMs, and that report has been released. The verdict: 'Based on the measurements and analysis reported herein, existing third-adjacent channel distance restrictions should be waived to allow LPFM operation at locations that meet all other FCC requirements, [with the exception of several minor technical requirements]'. There's more coverage at DIYmedia.net"

30 of 177 comments (clear)

  1. Hrm... by I+Like+Swords!!! · · Score: 5, Funny

    Can just imagine if the interference was a problem...

    All those DJs going "Can you hear me now?" every five seconds.

    --
    .unsigged
  2. Decent radio? by HomerNet · · Score: 5, Interesting

    Does this mean we'll be getting good radio stations now?

    Seriously, this is a good thing, especially if someone can find a way to harness this for some sort of digital traffic.

    --
    I have no tag line
    1. Re:Decent radio? by Rick.C · · Score: 3, Informative
      Does this mean we'll be getting good radio stations now?

      Yes. If you mean stations that play the music you like, then yes, you will.

      You will trot your geeky li'l butt over to here (if you're a digital geek) or to here (if you're a radio geek) and get yourself a transmitter. (You have to build and tweak the North Country Radio kit, but I think it has slightly better specs. I like my MPX96 just fine, and by buddy likes his PCS card, too.)

      Then you can play the MP3s you like and everyone else be damned!

      BTW, these are legal with or without the LPFM regulations because they're under 100mw. The range is about 100-200 feet, or up to a quarter mile with a longer antenna (but you might be pushing it, legal-wise, at that range.)
      --
      You were 80% angel, 10% demon. The rest was hard to explain. - Over The Rhine
      "Math in a song is good."-Linford
  3. I don't understand this news. by radiumhahn · · Score: 5, Funny

    I don't understand this news, but they can have my Mr.Microphone when they pry it out of my cold dead hands!

    1. Re:I don't understand this news. by wb8wsf · · Score: 4, Insightful

      This is very good news indeed.

      This is really a battle over control of the airwaves. America has given the broadcast spectrum to large money interests, and it shows. FM radio is so completely devoid of useful things to listen to (with the one exception of NPR, thankfully) that I've started listening to streamed broadcasts from the BBC, where quality, imagination and diversity still exist.

      With low power stations, you might see an increase in the divirsity of broadcasting again. Maybe. It would certainly allow for new and different stations, some silly, some serious and some seriously weird. That would be a wonderful thing to see.

      There were never any inferference issues here. Well, there were, but the interference was from the corporations which didn't want this to happen at all. A little 5W FM statation is not going to have much coverage, but it will make for some interesting pockets of color in an otherwise mostly vapid FM landscape.

      --STeve Andre' (wb8wswf)

    2. Re:I don't understand this news. by DMDx86 · · Score: 4, Interesting

      FM radio is so completely devoid of useful things to listen to (with the one exception of NPR, thankfully)

      FYI, NPR is one of the big lobbyists going against LPFM.

  4. Signal Bleed? by metalligoth · · Score: 3, Insightful

    The FCC screwed up FM from day one. Signal bleed on FM is .5 MHz, and the stations are all .2 MHz apart. I seriously doubt a bunch of low powered stations will make FM any worse than it already is.

    1. Re:Signal Bleed? by LostCluster · · Score: 4, Informative

      Seattle area has that - 104.3, 104.5, 104.7, 104.9 . Just noticed that last night.

      What you're actually hearing as far as I can tell is:

      104.3 KAFE Bellingham
      104.5 KMIH Mercer Island
      104.7 KEEH Spokane
      104.9 KFNK Eatonvile

      And the distance between those four cities is kinda the point. You as a listener can hear all four stations pretty well in your car in Seattle, but none of the four actually have their transmitters there. If you were standing next to any of the four stations towers, you'd likely hear just that station and the other three would be wiped out by the .5 MHz signal bleed, combined with the fact that you'd be quite a disatance from any of the three other stations.

      That's how the .5 MHz bleed and the .2 MHz seperation co-exists. The FCC never puts stations that close to each other right next to each other, there's always a noticiable distance between the stations. There plenty of spots where stations .2 MHz overlap, and most radios are good enough to follow the carrier of the station they're tuned to in that situation because there will be a dramatic difference in signal strengths between the two.

    2. Re:Signal Bleed? by wowbagger · · Score: 4, Informative

      Where are you getting that 500 kHz "bleed" value from?

      I've looked at more FM radio spectra than I care to count, and they've all been well bounded to 200 kHz - in fact, show me an FM broadcast station that has more than -60 dBc more than 200 kHz away and I'll show you an FCC engineer writing a Notice of Violation.

      Now, crappy old FM radio receivers may have had poor IF responses that wouldn't block an ajacent channel 500 kHz away, but that is poor design on the receiver, not a flaw of the format or of the transmitter. A modern system with a synthesized LO and crystal filters has no problem filtering signals at that spacing.

  5. Lower Power? by NetCurl · · Score: 4, Interesting

    I would assume that lower power FM radio stations would have lower overhead costs (power being one of them). This could allow for a subculture of small radio stations similar to public-access cult-followed TV shows.

    Media reform, here we come!

    --

    It's only when we've lost everything, that we are free to do anything...

  6. Free Radio by fm6 · · Score: 4, Insightful
    I have to provide a link to my local Free Radio Station. I never listen (they don't play anything to my taste) but I support them on general principle.

    Interference was always a straw man. Media monopolies like Clear Channel (yikes! how unintentionally appropriate!) just want to maximize the spectrum available for their musical monoculture.

    What I really miss is all those low-power campus and community stations. Yeah, they mostly played crap, but it was local crap. And it was a good way for budding young radio DJs and journalists to break into the field. I've always found it strange that NPR is on the "stop interference!" bandwagon, since all their best people come from the low-power community.

  7. The purpose of the FCC by spun · · Score: 4, Insightful

    The purpose of the FCC is to raise the barier of entry to the communications marketplace. It used to be about protecting a public good, the airwaves, but I think we can safely say, that is not it's real purpose today.

    Think what it would mean to someone like ClearChannel if anyone with a few hundred dollars could legally set up a low power radio station? In the San Francisco Bay area, people do it illegally, and they are really some of the only radio worth listening to here. No one would listen to corporate rock if there were little local alternatives.

    --
    - None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
  8. Newsflash! by bugnuts · · Score: 5, Funny

    RIAA filed 250 million lawsuits against every person in the USA, each of which has allegedly "received stolen music". Notable quotes are "Air should not be allowed to be used freely, as using the air is costing our artists millions of dollars. We are lobbying for a medium tax for everyone that uses air."

  9. If they allow low power FM stations ... by DogIsMyCoprocessor · · Score: 3, Funny

    to fill up all the gaps in the FM band, what will happen to pirate radio stations?

    --

    "And this is my boy, Sherman. Speak, Sherman." "Hello." "Good boy."

  10. Pirate Radio? by Gizzmonic · · Score: 3, Insightful

    I think we all know what this report is all about:

    Justification for pirate radio! I highly suggest that anyone and everyone buy a transmitter, and don't just absorb the radio: be the radio!

    Also, read Radio as a Means of Communication, A Talk on the Function of Radio, by Berthold Brecht. He seems to get it.

    The technical aspect of radio modulation has improved over the year. There's no reason why we can't trash FM/AM and adopt a digital technology that uses the same spectrum-that way, we wouldn't even have to trash your antennas.

    Your radio sets would probably be gone though. Oh well, I threw away my old style roller skates when I got some Rollerblades (R). Let's join hands and fart into the future!

    --
    (-1, Raw and Uncut is the only way to read)
  11. I have a FM transmitter already by teamhasnoi · · Score: 4, Interesting
    Its one of those real-estate "Drive-By Info" things. You can put a cassette in it (presumably looped) and listen to whatever.

    I'm guessing with a little hardware hacking, an additional input can be added and I can either tie it in to a net stream (Soma!) or run mp3s through it, and listen throughout the house and yard. Would make any walkman into a local-only mp3 'player'. I am reasonably sure that no licence is necessary.

    I just have to get an antenna. Damn these laws of physics!

  12. It was NPR's fault. by eclectro · · Score: 5, Insightful

    ostensibly because of interference concerns, and cut the number of stations from thousands to a few hundred

    NPR lobbied extensively to kill LPFM, primarily because they didn't want the competition with people listening to real community radio.

    So congress decided that they were "engineers" and said that there would be "inteference", and gutted LPFM.

    I don't pledge to NPR, and I am thinking of an "anti-pledge" campaign when they shill for money.

    Radio as we know it today is dead, primarily used for corporate interests, not the public's.

    --
    Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
    1. Re:It was NPR's fault. by Quickening · · Score: 3, Insightful

      no joke. I couldn't agree with you more. Over the past 20 years NPR has simply turned into another government PR office.

      --
      tcboo
  13. Protected != Reality by LostCluster · · Score: 4, Insightful

    Here's the reason why the big time FM owners are claiming that LPFM interferes but the studies don't back them up. The "protected countour" of an FM signal is not always the same as its actual coverage range. That is to say, some FM radio stations are heard loud and clear in places that the FCC's prediction model doesn't expect them to be, and conversely absent in others. The problem here is simple, a coverage map based on a topographical map will always be inaccurate because no map perfectly maps everything, and pesky things like skyscrapers sometimes have to be taken into account. Broadcasters have better technology, so they do a better job of guessing where their signal will actually go when they request approval for a tower site.

    So, FM stations will be able to produce listner complaints that say "I used to live in Wxxx's coverage range, but now some pesky LPFM from 4 towns over is jamming their signal out." The truth is, that listener was never in Wxxx's protected countor, the area where Wxxx has a right to complain to any interference with their signal, because the FCC's prediction system didn't expect Wxxx's signal to be there. So, when the LPFM interjects actual interference into the territory, the maps don't show any problemsome overlap.

    In some ways, this is a case of government not keeping up with reality. On the other hand, it's also a case of the FM station owners enjoying signal reach that the law never entitled them to. AM skip works the same way... distant stations can be heard at night when the weather is good, but even the former "clear channel" (lower case, meaning no other station on the same frequency, not the megacompany) stations now face stations on the opposite coast using their frequency and can't complain about being interfered with in those distant cities, just if something is going to bother them in their home territory.

    Just because the government lets something be the way it is for years without messing with it doesn't let a business assume it's going to be that way forever. LPFM is a great idea on the chalkboard, but a lot more work than most applicants realize. But, for those who can get it together, let them have the technology...

  14. Diymedia slashdotted, so heres the TOTA by Anonymous Coward · · Score: 3, Informative

    7/11/03 - Long-Overdue LPFM Interference Report Complete: No Third-Adjacent Channel Protections Necessary [link to this story]

    When Congress gutted the low power FM service enacted by the FCC in 2000, it reduced the number of available LPFM frequencies around the country by more than two-thirds by implementing "third-adjacent channel spacing protections." This forced LPFM stations to find a clear frequency with at least three channels separating it from existing local stations, which in urban areas is all but impossible. This single fact alone cut the number of potential LPFM stations from thousands to a few hundred at best, with most of those located in rural or suburban areas.

    The passage of the "Radio Broadcasting Preservation Act," however, did contain one caveat: the FCC was mandated to conduct an interference study to make sure the third-adjacent channel protections were necessary. The study was to be completed by February 21, 2001. It was actually finished in March, 2003, by the MITRE Corporation, who subcontracted the field testing of temporary LPFM stations in seven communities around the country.

    The Amherst Alliance, upon discovering the report was finished but the FCC was sitting on it, filed a Freedom of Information Act request in May to make it public. The FCC blew it off, and correspondence escalated to a point where members of Congress might have gotten involved and/or a lawsuit to force the disclosure might have been filed.

    This week, mysteriously, the 700+ page report was published in the FCC's Electronic Comment Filing System. No fanfare whatsoever, not even a note to those of us behind the FOIA effort to let us know it was available. The reason may be due to the following conclusions:

    "Based on the measurements and analysis reported herein, existing third-adjacent channel distance restrictions should be waived to allow LPFM operation at locations that meet all other FCC requirements [after four small revisions]...

    The FCC should not undertake the additional expense of a formal listener test program or a Phase II economic analysis of the potential radio interference impact to LPFM on incumbent FPFM [full-power FM] stations...Perceptible interference caused during the tests by temporary LPFM stations operating on third-adjacent channels occurred too seldom, especially outside the immediate vicinity of the sites where the stations were operating, to warrant the additional expense that those follow-on activities would entail."

    And the National Association of Broadcasters and National Public Radio, who played Congress like a fiddle by claiming that LPFM stations would wreak havoc with their signals, may want to chew on this tidbit especially thoughtfully:

    "In terms of the impact of an LPFM station due to interference on the audience of an FPFM station, in the worst case measured, the fraction of the protected coverage area of an existing station that could be subjected to harmful interference is 0.13%. In most other cases, this fraction is orders of magnitude smaller."

    Download the four main documents from the LPFM interference report here, in .pdf format:

    Section 1 (MITRE Final Report, 4.4 MB)
    Section 2 (Comsearch Field Test Plan, 2.4 MB)
    Section 3 (Comsearch Test Procedures Plan, 664K)
    Section 4 (Comsearch Field Measurement Data, 5.1 MB)

    A cursory glance through the field data collected for the report brings up some additional interesting tidbits.

    Comsearch (the subcontractor who conducted the field tests) placed public notices in the each test location's major newspaper and had announcements of the LPFM interference test played on the full-power FM station in the area closest to the frequency on which the test would take place. In each instance, no public complaints of LPFM interference were received, although interference complaints were received at some test locations that involved sources other than the test LPFM transmitter.

    Most interesting quote from the field data sec

  15. No, or at least not using traditional approaches. by Skyshadow · · Score: 5, Interesting
    Does this mean we'll be getting good radio stations now?

    No, it doesn't. Have you ever heard a pirate radio station? Generally it's someone with their MP3s on random play who cuts in for the occassional rant about how cool this is or how the FCC sucks or whatever. I can't imagine why the average low-power station would see an increase in quality just by going legit, except that it might drive away some of the more untalented people who aer just doing it because it's illegal.

    No, *I* wonder if you might not be able to think different here.

    Picture this: Rather than just a transmitter, you also set up a web feed of your programming. Other people who find your show can set up their own low power transmitters and rebroadcast it, and maybe add their own shows and content to the "network" (so I'd be on for a few hours, then the owner of another transmitter would be on for a while, making it possible to have live content for larger portions of the day -- this'd be trivial to set up).

    This would hopefully lead to a situation where democratic radio stations would emerge. If enough people like your content, the area in which it could be heard would grow as more transmitters are added. This could snowball to the point where, at least in urban areas, you'd have something like a real coverage area. If your show quality drops off, well, transmitter owners can go elsewhere.

    Would it work? You got me -- there might be technical or regulatory issues, and certainly there's no accounting for the taste of the masses, but it's still a more interesting concept than just having many pirate-wannabes broadcasting...

    --
    Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
  16. FCC Jurisdiction by metalligoth · · Score: 4, Interesting

    The FCC is given power from the Federal Government of the USA, which argues that it is regulating "Interstate Commerce", as per the Constitution. What most people don't realize is that in order for a radio station to fall under FCC jurisdiction, from a legal standpoint, the station needs to broadcast outside of a state's borders. (The only exception being if a state has made a law that the FCC has power in that state.) Otherwise, it is Intrastate Commerce, not Interstate Commerce. If you're in Michigan and your signal doesn't reach Canada, Wisconsin, Ohio, or Indiana, your station cannot be under the FCC's evil thumb! I know of at least one pirate station that has used this argument and has won in court. So, even if low powered stations can be regulated by the FCC, it doesn't matter as long as your station's power is low enough not to leave the state.

  17. LPFM? We need more local and internet stations. by banal+avenger · · Score: 5, Insightful

    I am significantly less concerned about the future of Low Power FM than I am about the fact that Clear Channel owns some 70% of the market. I haven't heard decent music on the radio in years, and (coincidentally) I hear the same music in Arizona as I did in Minnesota. Not only do I hear the same music, but I hear the same station names with the same cheesy slogans but with different numbers.

    Low Power FM isn't really all that useful because one is almost never in range to hear it. Minneapolis had a LPFM station for a while called The Beat. I lived 5 miles from the station and couldn't hear it. They were unliscensed and subsequently got shut down by the FCC in a well documented media event. The Beat now does a nice internet radio stream. And I think that internet radio has much more potential than LPFM ever will.

    The summary is Low Power FM just isn't all that. Internet radio can be all it could have been and more, and allows the user greater control and allows more distrubuters into the fold. This effort would be much better spent protecting internet radio and fighting back against companies such as Clear Channel.

  18. Re:No, or at least not using traditional approache by MattCohn.com · · Score: 3, Interesting

    You would still get those low quality radio hippies, but I belive the quality in general would improve. Why? Because the people who are going to do the crappiest job are the kind of people that WOULD set up a pirate radio station, whereas people like me who would do a decent job wouldn't dare might the FCC triangulate us.

    I'm currently writing a Windows-based radio station automation system (no jokes about the blue sound of death, almost all radio stations are run off Windows) modelled after OpLog (http://omt.net), and I would take the care and time to schedual, voice track, and even go on live when I had the time. Not only that, but I have a good taste of music (to me).

    I personally hope the FCC gets off their asses and does something good for the PEOPLE once instead of Entercom and Clear Channel. Does anyone remember when 'The Airwaves Belong[ed] To The People'? I think it was back when ONE company could own ONE FM, ONE AM, and ONE TV station in a single market.

    So, from this I'm sure you can tell how I fell about the new legislation Clear Channel and Entercom passed through the government allowing single corperations to own EVEN MORE stations in a single market.

    I hate you FCC.

    I hate you Clear Channel.

    I hate you Entercom.

    If the airwaves belong to the people, why can't the people own them?

  19. Where to buy FM broadcast equipment. by Anonymous Coward · · Score: 3, Informative

    Trust me, you don't want to use hacked Mr. Microphones or real estate promotional transmitters to get on the air. If you're interested in broadcasting, affordably, with an FM transmitter, and you are halfway handy with a soldering iron, check out the kits this British outfit sells (they ship internationally):

    http://www.broadcastwarehouse.com/ (click Kits, Modules & Parts)

    Pretty easy to put together and they work very well. Or you could buy one of their pre-assembled jobbies.

    Another company specializing in FM kits is Veronica:

    http://www.veronica.co.uk/

    I built one of their 1 watt PLL kits, and also purchased a 25 watt amp. Great stuff, cheap, well designed. Buy a Cushcraft vertical antenna and you're on the air in style.

  20. Interference and junk radios by Anonymous Coward · · Score: 3, Informative
    Buried in the conclusions is the annoying cause of the third-adjacent-channel interference. The best receiver used for testing had less than 60dB rejection of the unwanted station; typical portable radios had less than 30dB. In simple language, that ranges from mediocre performance to "sucks rocks". If you lived 250m from one of Clear Channel's 50KW transmitters, that would block an independent 1KW station 25km away from you--with the least-bad receiver they used. If it's the worst, the indy would have to be less than 2km away to be heard.

    The problem isn't the LPFM station, it isn't the FPFM station, it's the poor selectivity of FM receivers. 50-60dB is entirely practicable for low cost portables, and at least 80dB should be the norm for higher priced home audio equipment. But the honest truth is that manufacturers aren't going to give you any better performance unless customers ask for it (ie, complain). They can use every channel in sub-$100 "cable ready" TV sets, so they can certainly build affordable "high signal density" FM radios--if there's a market for them.

  21. Hunh? You are SO wrong! by mekkab · · Score: 3, Informative

    IANAL, but my wife IS, and is currently studying for her BAR exam. Why is that of interest? The Constitutional law part.

    It seems that literally ANY point can be argued as a breach of the commerce clause.
    As proof I give you Katzenbach v. McClung. (ollie's BBQ)

    A tiny, tiny local BBQ joint didn't want to serve blacks (only allowed take-out). Title II of the Civil Rights act claim is made against BBQ joint.

    from THis website: Katzenbach v. McClung,44 (Ollie BBQ), held that since 70% of meat served at a restaurant located only 11 blocks from a major interstate highway is subject to interstate commerce, noting a "rational basis" for finding discrimination in restaurants had a direct and adverse effect on free-flow of interstate commerce."


    Your paper plates could come from out of state. POWER and Electricity can come from out of state. Telephone service, etc.

    Every BAR prep course recommends you trot out the commerce clause to question the constitutionality of anything- because its so damn broad.

    P.S.- when I showed her your post, she giggled.

    --
    In the future, I would want to not be isolated from my friends in the Space Station.
  22. Public Access Pirate Radio by Dan+Crash · · Score: 4, Interesting

    I can tell you what worked for us.

    In the year 2000, we hooked our 150 watt transmitter up to the Internet and hung a banner over a Mpls/St. Paul I-94 overpass with our website spray painted on it.

    Visitors to the website could upload any MP3 off their hard drive to the station and it would be automatically queued up for broadcast. We also set up a voicemail line for those who didn't have computers -- any voicemail left there would be automaticaly queued up for broadcast as well.

    It was great radio for the 2 weeks straight that it lasted. The best I've ever heard. We got several hundred uploads and voicemails on the air. When we ran the same station promos too much people began making their own and uploading them. It was wild.

    When the FCC agents found our transmitter, we had to go on hiatus. We've worked on improving the software we use, and we may do it again someday. I think a model like this -- with some substantial tweaking -- could make microradio stations the most fascinating audio in town.

    --
    He who refuses to do arithmetic is doomed to talk nonsense.
  23. Bah. by Cinematique · · Score: 3, Insightful

    It's sad that a local station is allowed to spew 50,000 watts of Country music into the air, overflowing into adjacent frequencies, but if someone broadcasts a stable 1,000-watt signal, they're (still) doing something against the law.

    Me, bitter? Nah...

  24. I wonder why no one is talking about low power AM by multiplexo · · Score: 4, Interesting

    in the 1630 to 1710kHz range. The FCC opened this up in the late 1980s and it remains largely unused. Sure, people are going to whine and say that AM broadcast quality isn't as good as FM, but I'd rather listen to an interesting station on AM, with the occasional crackle of static, than perfectly clear corporate clear channel crap on FM. It seems to me that the FCC could take this space and rededicate it to community low power AM stations.

    --
    cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.