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Boston TV Signals Disrupting Police Radio in NJ 345

jeffy124 writes "WCVB, a digital TV station in Boston, is disrupting police radio communications in South Jersey. It seems that under certain weather conditions, the signal reaches here travels 270 miles (it's normally 50) and blacks out the police frequencies, making communication between officers and from 911 call centers impossible. The article seems to suggest that as more TV stations go digital, more small-town police radio will be affected, as the digital signal is significantly stronger than analog. Insert Joisey-joke here."
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Boston TV Signals Disrupting Police Radio in NJ

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  • by NotAnotherReboot ( 262125 ) on Saturday November 02, 2002 @12:38AM (#4582538)
    I think it's a safe bet that we'll see more donut commercials on digital television broadcasts- it ensures that it reaches the best possible demographic that will be influenced by donut commercials (cops, of course).
    • Well, you've forgotten about the recent economic downturn. I never realized just how bad it was until a friend told me about a cop who was a friend of theirs. It was so pathetic somehow--with his budget, he could no longer afford donuts... :]
    • OK I'm in position

      Cue the comercial...now!

    • You're living in the days of Mod Squad and Adam-12. Come out of your cave once in awhile. You think you're being funny, and it possibly would have been... 20 years ago. It's an immature and childish cliche' to suggest Law Enforcement Officers are donut gobbling neanderthals. The fact is, the vast majority of L.E. Officers are physically fit and avoid eating donuts or camping at donut shops. Donuts are for couch potato computer nerds who have nothing better to do than flame people who would give their lives to save your and your loved ones, and have... far too much for the likes of you. The tables have turned NotAnotherReboot, YOU are the demographic they seek to entice.
      • True Story -

        I have a friend who serves as a supervisor for a local police department - at a party he related the following story:

        "So John, how was your week."

        John replies: "Really bad, we had an officer involved shooting and it was embarrasing."

        So I ask the obvious. "Why, was he at a donut shop or something."

        John moans and says "Yes."

  • Joisey Joke (Score:5, Funny)

    by Anonymous Coward on Saturday November 02, 2002 @12:41AM (#4582545)
    NJ got all the toxic waste dumps. You see, California drew the short straw and got all the lawyers.

    • California and Texas both have more superfund sites than NJ. And Gary, Indiana puts Newark to shame
    • by Lucas Membrane ( 524640 ) on Saturday November 02, 2002 @02:42AM (#4582843)
      It's true about NJ mosquitoes. They've adapted and actually are attracted to mosquito repellant. When a busload of tourists comes to the Jersey Shore from NYC loaded with mosquito repellent, the mosquitoes go into such a frenzy that they actually bite the picture of the greyhound on the side of the bus. Within a few hours, the bus is so swollen that it can't fit back through the Lincoln Tunnel.
  • by Skirwan ( 244615 ) <skerwin AT mac DOT com> on Saturday November 02, 2002 @12:42AM (#4582547) Homepage
    Insert Joisey-joke here.
    I broadcast in Joisey. Do you broadcast in Joisey? I broadcast in Joisey.

    Really? What frequency?

    --
    Damn the Emperor!
    • by Loki_1929 ( 550940 ) on Saturday November 02, 2002 @04:36AM (#4583066) Journal
      Score 5 Funny?

      I'm guessing the moderators who modded that up have never actually been to New Jersey. Now, for one thing, the Meadowlands (up north close to NYC) is the only place that's even remotely smelly or of poor conditions in NJ that I've seen so far. Much of southern NJ was made up of small farming communities until recently when actual townships started forming. Most of NJ is now just that; small townships with hardly anything in between but trees, connected only by small (two lane) roads. I just moved to NJ a few years ago, and I'm not offended by comments - just the ignorance that their content shows. If you want to make a joke, call the people here simple, or make a comment about how almost everything is closed after 6pm, or how there's so much farmland. There's no accents in New Jersey; you're thinking of certain sections of NYC. These are (for the most part) normal, simple people who are MUCH friendlier and happier than the people from the DC-metro area. No one here says "joisey", we say "jersey". I must admit, however, that I was a bit surprised when I moved here from Maryland and couldn't find someone with any accent for a while.

      Oh, and by the way, our gas is cheaper than most places in the country, and it's full service everywhere (state law). When my relatives in MD were paying $1.90 for gas, we were paying $1.25. NJ isn't such a bad place when you actually take a turn off the NJ Turnpike.

      • There's no accents in New Jersey

        Typical American attitude (I can say that, I'm one too). Everybody has an accent -- just because you sound like the people you see on TV doesn't mean that you're talking the normal way and other people have a weird accent that's a deviation from that. Sorry, just... no.

        Anyway, how about instead of the usual Joisey jokes, we make fun of you all for being too damn defensive?

      • I hate to jump on your comment since you're very right about what NJ is like and your point is a good one. But this is Slashdot, so I'll nitpick.

        I grew up in Delaware and have several friends from Jersey (and New York). I've also studied several of the regional dialects, and there certainly are accents in New Jersey. They are similar, but not the same as New York accents. The classic 'Jersey' accent that most people think of is sometimes more a matter of tone than it is inflection. It shares some things with the Brooklyn accent, such as some vernacular -- 'forgetaboutit' and 'whaddyagonnado,' etc.

        That said, there is, of course, no one Jersey accent, and perhaps what you meant to say was that the classic Jersey accent is not present in all of Jersey. I was fairly close to Camden. Although it's ugly as sin (approaching but not quite on par with Newark), I've never heard an accent in anyone I know from there. Nevertheless, I've heard variations on the Jersey accent in central and northern NJ, and it is prevalent enough to be 'The Jersey Accent.'

        Excellent point about the gas though. And I absolutely agree that NJ is a decent place.

        -SWK

  • Digital TV (Score:2, Interesting)

    by Mitreya ( 579078 )
    Maybe this will slow down the adoption of the Digital TV...
    • What do you have against DTV/HDTV?
      • Re:Digital TV (Score:5, Interesting)

        by Mitreya ( 579078 ) <<moc.liamg> <ta> <ayertim>> on Saturday November 02, 2002 @02:02AM (#4582762)
        I have nothing against DTV/HDTV.
        I did get the impression that it is being forced down our collecive throats since it has not been adapted quickly enough by the market.

        I feel that the regulations are being applied to the *wrong* industry. Wouldn't it be much better to mandate that all vehicles must be electrical or hybrid by 2007? As much as I like my car, I can see the advantage of such law. but TV phase out? for what? for Hollywood quality content that they have been withholding? :)

        • I did get the impression that it is being forced down our collecive throats since it has not been adapted quickly enough by the market.

          See the thing is, the Manufacturers are reluctant to mass-produce HDTV devices because there isn't enough demand for it, and availability of networks who put out the signal is limited compared to regular stations. Hence we see the inflated prices for HDTV receivers, which can certainly come down drastically if mass-market consumption improved. Since all of the Digital ready devices out there can receive regular signals, I don't see how this is a problem. There are many network shows out there which simulcast shows both in HDTV and the regular way (ex. Tonight Show).

          Anything that limits technology is a bad thing.

          I generally do not believe the technology is being "shoved down our throats" fast enough. It's not like the regular TV vanilla signal is going to go away anytime soon.
        • Re:Digital TV (Score:3, Interesting)

          by Shadow99_1 ( 86250 )
          It's being forced on us because people are inherently dumb. People hate change (of just about any type) & this has hurt certain things. DTV/HDTV being one of them, other countries have something like it already (Japan) or are working on it (Europe & Australia).

          I'm biased on the whole issue because I own an HDTV. HDTV is simly amazing. I've seen people watch an HDTV loop of various locations of the country for hours & this was a 10 minute loop (so it repeated for ~10 times before they could pull themselves away). It's also great for gaming as it lets games from a console system rival the quality of PC games, of course the only system designed to output in HD is the xbox but the next generation of consoles will most likely all support it...
        • Re:Digital TV (Score:3, Insightful)

          by gadget_ts ( 622271 )
          It is being shoved down our collective throats! I have nothing against technology but there is something definitely amiss with this issue. HDTV and Digital Radio is not worth the price that we will have to pay and I am not just talking about money. Why is this such a priority for the FCC? There has to be money involved.... lots of money and we are the pawns. KEEP IN MIND... that this will edge out low-cost independent broadcasting because of the way the FCC has chosen to implement it. I am as tech hungry as the anyone but a B&W, 5" screen, analog TV for much of my watching needs is just fine. When HDTV if fully implemented I will no longer be able to use it. Digital braodcasting hands over control to the handful of huge media companies. They can control copying (recording), etc..... We have been sucked into DVD's. Which are nice but it controls copying of the media. We were sold on the digtial picture and sound but in reality it has giving the media companies control over copying. Something is wrong here folks. We should all step back and look very carefully at what we are giving up for a pretty picture. Is it worth it?
  • It's called (Score:5, Informative)

    by pa-guy ( 457151 ) on Saturday November 02, 2002 @12:43AM (#4582550)
    tropospheric ducting.
    • Re:It's called (Score:3, Interesting)

      by Xtraneous ( 594376 )
      Tropospheric ducting is your friend! Actually my first experience with tropospheric ducting was on a sunday night around 10pm, and I was able to reach a radio station in Ironwood MI (about 250miles from where I am,) with fairly decent quality. What was playing in Ironwood? Well... simple, Hearts of Space. [hos.com] IMHO one of the best radio shows around.
      • An Amateur friend in Albany [detailed PDF, 300kB] [wa.gov.au] [grotty GIF, 29kB] [wa.gov.au] [GIF of context, 9kB] [wa.gov.au] was listening with half an ear one day while doing other stuff, when he suddenly realised that he was overhearing local traffic in Adelaide [clickforaustralia.com]. So he wound his 1KW linear amp down to (IIRC) 4W, clicked on and said `Hi, such-and-such', naming one of the participants instead of using a callsign. He ID'd later in the conversation, and there were some thuds of dropping jaws when he did.

        The duct covered roughly 1600km LOS [clickforaustralia.com] on a few watts. I don't know if that's a record, but it certainly impressed me.

      • Re:It's called (Score:3, Interesting)

        by mesocyclone ( 80188 )
        Years ago (almost 40!), I was a transmitter engineer at KANU-FM (110KW, Lawrence, KS - University of Kansas). One night we got a call from a station in Florida that was on the same frequency. They had shut down their transmitter for maintenance, and our signal immediately started coming in on their studio monitor.

        I also used to monitor the local police, who in those days were operating on VHF Low Band (30-50 MHz). That same ducting caused some southern, very rural and very hick-like (this was the 60s) sheriff systems to come come in on the same frequencies. Things got really wierd - especially since neither side knew what was going on.

        Tropospheric ducting is kewl.

    • Gratuitous link (Score:5, Informative)

      by Anonymous Coward on Saturday November 02, 2002 @01:04AM (#4582610)
    • by KernelSanders ( 166914 ) on Saturday November 02, 2002 @01:29AM (#4582670) Homepage

      VHF / UHF Tropospheric Ducting Forecast Maps [globalserve.net]

      These maps graphically display unstable signal areas.

      Quote from the website:

      The areas noted in the forecast have the necessary atmospheric conditions to produce tropospheric bending of UHF or VHF TV and radio waves. Tropospheric bending extends the range of stations well beyond their normal limit. Distant reception along straight line paths becomes possible..though the longer the path, the higher the Index required. The pursuit of distant stations is called "DXing".
    • Umm, yes. It says that in the article.
    • Re:It's called (Score:2, Informative)

      by mdechene ( 607874 )
      I was actually at a presentation today where a RF Engineer from Nextel, I think, was talking about the same thing happening.

      Apparently, when there is a layer of hot air above a layer of cold air (it's normally the opposite), the Snell's law can be satisfied for total internal reflection conditions. In other words, Nextel found that on certain days in the middle of the summer, they dropped like 60% of their calls on certain cells, as opposed to say 2% as is typical. Turned out that nearly all of the dropped calls were originating on the Michigan side of Lake Michigan, bouncing off these "inversion layer" ducts, and the phones were camped to Wisconsin base stations over 70 miles away.

      Anyways, Nextel angled their antenna's down and decreased the power output somewhat, effectively minimizing the footprint, and the problem has been reduced (but not completely eliminated). Also interesting was that this thing seems to be much more likely to happen over a large body of water. They seemed to think in summer, the water cooled the air and then warm air blew across the cool layer. Apparently cool air has a higher refractive coefficient than warm air.....
    • When I lived in Hawaii, I witnessed tropospheric ducts between Hawaii and California that made it possible to talk to amateur radio operators in California on the 144 MHz amateur radio band with relatively low-powered FM transceivers. That is about 5000 miles for a frequency band that is normally line-of-sight propagation. It would usually happen a few time a year. You had to be at the right altitude in Hawaii to get a signal into the duct.
  • Joisey Joke? (Score:5, Interesting)

    by thesolo ( 131008 ) <slap@fighttheriaa.org> on Saturday November 02, 2002 @12:44AM (#4582555) Homepage
    Ok, this is slightly OT, but speaking as someone who lives in Southern NJ, I would like to state for the record that no one around here speaks with that type of accent. We all pronounce Jersey with the letter R, thanks!

    Most people have a large misconception about New Jersey, especially thinking that it all looks like Newark, every woman has huge hair and long fingernails, and that none of us pronounce the letter "R". While this isn't entirely untrue (head up to Northern NJ to see what I mean), it does not describe the area of NJ being affected by the Boston signals. As I always say, they should split up Northern & Southern NJ, and combine the Dakotas. :)

    Back on topic, I saw this story on the local news here tonight. It's a very big problem, as peoples lives can potentially be at stake. This is something we will be seeing a lot more of in the future; we already have frequency problems with 802.11, and now it seems that TV broadcasts will be continuing the trend.
    • Re:Joisey Joke? (Score:2, Interesting)

      by jeffy124 ( 453342 )
      Italians living in north jersey decades ago pronounced it "joisey" at first, which is where it comes from. It tended to stick around in joke capacity.

      As for the main topic, I too first saw it on local news, then went looking on GoogleNews. I live in Clementon - which uses the Lindenwold 911 Call Center discussed in the article, so I'm definitely concerned.
    • Laser light show (Score:2, Interesting)

      by wwwgregcom ( 313240 )
      Alright now I have to speak up. I live in north jersey and no one here speaks without the "r", in fact ive never even heard that. What we do do though is turn some "a"s into "o"s. Ex: its not tomato its tamato. Looks weird on print but it sounds right to me.

      About the newark thing, some of jersey does look pretty damn shitty, but if you go west, belive it or not, there are farms, with real cows. I live in a pretty rich area and I think its beatiful here. Belive it or not, I love NJ!
    • "(head up to Northern NJ to see what I mean)"

      What exit?
    • "It's a very big problem"

      It's happened twice in one month, and neither time were any lives in immediate danger. As for the future, the FCC is stepping in and meeting with local officials to work out a solution, so I wouldn't worry about it. From everything I've seen, the FCC doesn't screw around when it comes to 911.

  • Same frequencies? (Score:2, Insightful)

    by Spazmania ( 174582 )
    How is it that the FCC registered digital TV frequencies overlap the FCC registered police emergency frequencies at all, miles apart or no?

    Are we talking too much power on the TV's sideband, bleeding into the police frequency?

    Are we talking a grandfathered police operation when the frequencies were reallocated to digital TV where the cops have had years now to realize that they were playing with fire and replace their communications system?

    Surely the FCC didn't intentionally allocate a police frequency smack in the middle of the exact same bands they set aside for digitial TV. So what's the real story?
    • by damiangerous ( 218679 ) <1ndt7174ekq80001@sneakemail.com> on Saturday November 02, 2002 @01:30AM (#4582679)
      The "real story" would be the article. Which contains the answers to every single one of your questions.
    • Re:Same frequencies? (Score:3, Informative)

      by mobets ( 101759 )
      Yes, our 'friends' at the FCC have been selling Digital TV channel 20 to police stations. The city bought those frequencies in '98. or maybe they trurned a band used for police into channel 20. Either way, they should have seen this comming. My question is what they were planning to do when Digital TV becomes more common.
    • The article does not address the point.

      Public safety radio communications started out in the VHF low-band (30-50 MHz) back in the 1950s. As usage grew, they expanded into the VHF high-band (150-174 MHz). Eventually, all of the VHF channels were exhausted in many major metropolitan areas. To accommodate further growth in public safety communications, the FCC allocated parts of the low end of the UHF TV band (470-512 MHz, equivalent to UHF channels 14-20) to public safety communications in selected areas. This had to be coordinated with existing UHF TV stations that already used that part of the UHF TV band. For example, there may already be UHF TV stations on channels 14 and 20. Public safety users can be allocated frequencies in between channels 14 and 20.

    • For years the FCC has allowed police departments to share UHF-TV frequencies in many metropolitan areas. Scanners call this the UHF "T" band, T as in Television. For example, in the Boston area TV channels 16, 17 and 18 are used by the Boston Police Dept. and many others. Most of the sharing occurs on UHF TV channels below channel 25. This wasn't a problem with analog TV signals as they are AM modulated. The radiated power distribution in the NTSC (analog TV) sidebands falls off quickly once you are off carrier. With digital TV, the radiated power envelope extends across the entire 6 Mhz TV channel. This is why Boston digital 20 interferes with New Jersey but the analog TV station operating on channel 20 in Waterbury, CT (MUCH closer to NJ) doesn't. The FCC has really booted it with Digital TV in this 30 year + Broadcast Engineer's opinion.
  • by Papa Legba ( 192550 ) on Saturday November 02, 2002 @12:57AM (#4582594)
    I work for a PBS station in VA, WHRO. We are currently being sued by a station WBOC-TV Salisbury, Md to stop the rollout of our Digital TV because it disrupts their signal on the Chesapeake side of the water.

    From what I understand of the problem their were bad assumptions made by the FCC when it came to the digital signal.
    1. That it would not bounce and doppler like analog signal does. Well it turns out it is even more prone to it than analog was due to the higher frequencies and watages involved.
    2. That this would not affect a $Properly setup atena. Seems reasonable until you find out what the variable properly is. Apparently the FCC does not care about interference unless the atena is aligned directly towards the sending tower (that never happens and varies from channel to channel) and that it is not higher than 30 feet (one story home. Any deviation from that and it becomes your problem, not theirs.

    This is also not the first case of this to happen. Their are previous cases in california and milwauke. Read more [tvinsite.com]
    here

    This is going to crop up as more and more channels go digital. You will start seeing it reported more as stations start to battle each other. The sad part is that most likely the FCC will wash their hands initally and the airwaves will become as if the FCC does not exist.

    • by Skuld-Chan ( 302449 ) on Saturday November 02, 2002 @02:44AM (#4582847)
      That it would not bounce and doppler like analog signal does. Well it turns out it is even more prone to it than analog was due to the higher frequencies and watages involved.

      Somewhere a ham radio operator is crying.

      I think the term you are looking for is propagation (the way signals travel through the ether) :). In general doppler shift isn't that much of an issue unless the transmitter is moving very fast (like a low earth orbit satellite)

      I have no idea what frequencies digital tv stations operate on, but in general on uhf tropospheric ducting is pretty rare - at least where I live.

      Where analogue tv channel 2 (around 57 mhz) long range propagation is pretty common, but thats not tropospheric ducting - thats sporadic e layer propagation.

      Past tv channel 7 tropospheric ducting is relatively common.

      Past tv channel 13 tropospheric ducting still happens, but its not nearly as common.

      I don't see why the mode would matter - I think digital television is a spread spectrum signal. If done right you should be able to operate other ss devices in the same frequency space. Narrow band radios recieve ss signals as low background noise typically - so that should be an issue. I wonder what the real interference problem is?
    • It seems to me a rather bad and outdated idea to try broadcasting digital signals in this method.. using lots of power and just blasting the signal out for miles around. It makes more sense to devote more of the spectrum to the public it belongs to and use wireless networking to route the data intelligently to where it needs to go. If I can stream a DVD-quality movie over a fairly congested WiFi network at home I don't see why television couldn't be broadcast in the same way and quite a lot cheaper than building an expensive tower and licensing your own spectrum. The mesh networking units /.'d yesterday look like they'd work for this with few tweaks required. I'd probably create a smart routing protocol that'd let multiple users view the same stream rather than copying it along the route for each user but that isn't a new concept so it'd probably be possible to use off the shelf technology for that also.

      Anyone else find it odd that their cell phone and wifi equipment works fine but emergency dispatch equipment goes in the shitter? I knew the FBI used cell phones (well on X-Files at least) for good reason. :)
    • I do hope you're talking about an "antenna", because I've got no idea what an "atena" might be.
  • Go go FCC! (Score:2, Interesting)

    by MacAndrew ( 463832 )
    I used to do a lot of flying and can attest that high-frequency navigation signals travels maybe 70 miles line-of-sight at 2000 feet -- the height of some broadcast antennas -- and farther at higher altitudes. But reflections were weak or nonexistent.

    Communication frequencies, and this is aviation only, numbered some 720 (it's been a few years). Police communications are probably just as narrow and could be slotted any number of places, and being low-altitude would not cause much town-to-town interference. But instead they plant it in a frequency spread reserved for TV? (TV channel bandwidth is astonishing, dominating most of the available spectrum to deliver Gilligan's Island reruns and professional wrestling.)

    I know some people are excited by the advent of digital programming -- no, wait, actually I don't know any, though most agree it looks neat -- but the way the equipment manufacturers and FCC colluded to ram digital down the throats of consumers and broadcasters stinks. I for one will hang onto my analog set until the picture is no more than a faint flicker.
  • geez! (Score:5, Interesting)

    by jeffy124 ( 453342 ) on Saturday November 02, 2002 @12:58AM (#4582596) Homepage Journal
    Ok, I'm the submitter. I see a few posts denouncing the "Joisey" reference. I'm from NJ. It takes a sense of humor to live in NJ. I know that SJ is vastly different from the smokestacks of Newark.

    Am I the only person who lives in NJ with a sense of humor?

    (oh, and for the record, I live between exits 3 and 4)
    • Dude, why keep pushing "the jersey myth" to the public?

      Respect your state and show some pride!
    • It takes a sense of humor to live in NJ because the state is one big joke. :)

      I live in Northern Jersey, and have to say I don't hear much people with the Joisey lisp either. It must just be all the Boston people who moved here who don't pronounce their R's.

      FYI for people who don't live here, the smokestacks of Newark are well.. in Newark. Once you get away from Newark and the immediate NYC metro area (Hudson County, etc) it gets really nice. Before I moved here, I had only seen Newark and the view from Manhattan.

      For those of you who are interested in seeing the nature side of NJ, check out the NJ division of Parks and Forestry. http://www.state.nj.us/dep/forestry/parknj/

      • The Weird NJ site [weirdnj.com] speaks volumes about New Jersey.

        Living there is so weird that once you've gotten used to it, you will believe nothing and everything. Belief becomes a fairly meaningless concept in several ways.

        It is something of a tragedy that a state as populous as NJ doesn't have just about any local broadcast industry anymore. Getting signals from Boston is not any worse than the steady diet of NYC and Philadelphia programming that NJ residents must endure. Everyone who grows up there has sort of a builtin inferiority complex from living in a state with virtually no TV, no media of its own, coming from a place that doesn't even recognize itself except as the place where Hoffa is buried. This being the state where RCA developed much of TV, and where Armstrong built the first FM broadcast station, it's a shame. And you can't even get out of the state without paying a toll.

        • My wife is a big fan of Weird NJ magazine.

          After learning about "Geocaching" (a new hobby of finding/hiding things and posting the GPS coordinates) led me to this guy's website...

          http://www.gpswnj.com/

          It takes the Weird NJ info one step further, and actually provides GPS coordinates for places he's been.

    • Largely off-topic but entertaining nonetheless. In the words of Gorka [johngorka.com] (A New Jersey resident):

      I'm from New Jersey, I don't expect too much
      If the world ended today, I would adjust.
      I'm from New Jersey, no I don't talk that way
      I watched too much TV when I was young
      I'm from New Jersey, my mom's Italian
      I've read those mafia books, we don't belong.
      Girls from New Jersey who have that great big hair
      They're found in shopping malls, I will take you there
      I'm from New Jersey, it's not like Texas
      There is no mystery, I can't pretend
      I'm from New Jersey, it's like Ohio,
      But even more so, imagine that
      I know which exit, and where I'm bound,
      Tolls on the parkway they will slow you down.
      New Jersey people, they will surprise you
      'Cause they're not expected to do too much
      They will try harder, they may go further,
      'Cause they never think that they are good enough
      I'm from New Jersey, I don't expect too much
      If the world ended today I would adjust
      I would adjust
      I would adjust

      Actually who wrote the original version of this song? I'm having trouble remembering now...Anyway fwiw, I'm from South Jersey myself. We don't have the accent, but it's exit 7a, we have far too many shopping malls, the italian mobsters are everywhere, and it's slightly hilly/grassy with cows all over the place.
  • by Have Blue ( 616 ) on Saturday November 02, 2002 @12:58AM (#4582597) Homepage
    I heard this once but never confirmed it: Is it true that Air Force One's broadcast system uses the same frequency as, and occasionally interferes with, garage door openers?
    • by borgboy ( 218060 ) on Saturday November 02, 2002 @01:13AM (#4582635)
      hmmm....I dont know. I do know that Air Force One does have a large array of different comm systems in place, including UHF SatCom and I believe Iridium-style gear. But to call it "AF1's broadcast system" sounds a lot like you're saying it has only one communications system, which is certainly not the case. AF1 has to communicate with NORAD, the Pentagon, the White House, not to mention being capable of patching into the conventional phone network.
  • Wow. Now they can listen to, "Bad Boyz, Bad Boyz, ah-watch-a gonna dooooo? ah-watch-a gonna dooooo when dey come foh yooooooo?" when they are parked outside Hardees at 3 am, and pretend they're in high speed pursuit with those rascals from Hazzard County - The Duke Boys!

    I can see it now: "We better get over to Maple and 10th, Sergeant Friday is making a bust; it sounds like the perps got 'Reefer Madness' and Ponch is down, I repeat PONCH is DOWN!"

  • I honestly don't see what the big deal is. Radio interference where a signal travels farther than intended and interferes with other communications is an old problem, and inherent in most communication methods in use. Its a technical problem, and should be treated like one with resolution in an objective manner. The digital T.V. station should probably change the frequency its using (since the police radios may not be able to without buying new ones)
  • by euxneks ( 516538 ) on Saturday November 02, 2002 @01:27AM (#4582667)
    [cop] breaker breaker we have a
    *shhkt*
    Johnny!. Don't you walk out on
    *shhhkkt*
    a caucasian male running down to
    *shhkkt*
    The LOVE boat...
    *shhlkt*
    suspect changing direction, now he
    *shhhkkt*
    was the president of the united states, saying
    *shhhkt*
    God dammit! where the hell is that
    *shhkt*
    sheik condom. Barely there for the most pleasure

    =)
  • Insert Joisey-joke here.

    Why did the chicken cross the turnpike?
    To go down the shore for a grinder.

    He didn't specify funny Joisy joke . . .

  • FCC regs... (Score:3, Informative)

    by TheHawke ( 237817 ) <rchapin@nOSpam.stx.rr.com> on Saturday November 02, 2002 @01:35AM (#4582699)
    Under FCC regulations, any interference with official bands (IE, police, fire, ambulance) by a TV station is considered illegal by law and MUST immediately stop of be fined per day per channel that experiences the interference.
    This occurred with one cable TV station over in one town that i stayed in. They had brought up another channel into their lineup using AINCENT cable equipment that generated a harmonic with the City police's repeater and caused massive interference with their communications. The city immediately moved and filed a complaint with the FCC on this and the Gov't submitted a court order stating that the cable company shut down ALL services until this issue was cleared up. The channel was immediately shut down and the station was shifted to another channel that was more clearer and did not cause any further problems.
    • Emergency radio equipment is typicaly Part 15. it must accept any interference, and may not cause interference.
    • Actually, the situation you're describing reflects a loophole the cable industry got written into law. Cable systems shouldn't be leaking noticeable power outside the cables, but some of them do. The cable industry, to avoid the expense of keeping their systems RF-tight, got the rules revised so that they only have to fix such problems if they interfere with public-safety systems. They used to have to fix it if anybody complained that the cable system was interfering with anything. The FCC used to make them drive a truck along every cable route every year, looking for RF leaks. Now they don't have to do that.
  • Insert Joisey-joke here.

    Hey! We don't really tawk like that.
  • Reporter: How does this make you feel, knowing that cops may not be able to receive necessary 911 information? Area Man: Heh, heh. Fuggiddaboudit.
  • "Slashdot, new for nerds, stuff that matters"

    First there was the pumpkin PC, then the Dune book, and now a story that takes pertains only to NJ. I am officially suing slashdot for breach of contract.
  • Minor corrections... (Score:5, Informative)

    by KC7GR ( 473279 ) on Saturday November 02, 2002 @02:33AM (#4582828) Homepage Journal
    From the /. article header...

    "The article seems to suggest that as more TV stations go digital, more small-town police radio will be affected, as the digital signal is significantly stronger than analog..."

    Actually, the type of modulation (digital or analog) has little to do with the signal "strength" (which is a function of transmitter power output, transmission line losses, and antenna design and orientation).

    Now, with that said, digital modulation, being much closer to a square wave than an analog voice signal, is much richer in HARMONICS than said analog signal.

    I've lost count of how many times I've heard interference from digital paging transmitters bleeding into ham radio repeaters. The harmonics from the digital modulation mix with the transmitter's carrier, and that of whatever other transmitters happen to be on the same hilltop, and close to the same frequency range. It sounds awful, and it looks even worse on a spectrum analyzer screen.

    The problem may be correctable through (as others have pointed out) better receiver design, in terms of filtering, and good installation practices being followed where the transmitter and antenna system are concerned. Good filtering and modulation techniques at the transmitter end won't do any harm either.

    • See comp.risks from a couple of weeks back. Digital TV receivers are causing interference with digital cellphones within a couple of rooms of the TV set. This is a way to protect the TV stations from unwanted competition, as most of the dialogue on cellphones is funnier than anything on TV.

      Speaking of funny, law enforcement in NJ probably fits that category. Back in Hudson County, the police used to get extra pay when their duty was to guard the bootleggers' beer pipeline. I once almost got thrown in the hoosegow for slander because I had asked a fellow if he was the police chief. He was. He didn't like the insinuation. The feds had just raided the various organized crime locations doing vice in his locale and had made sure that he knew nothing about it until after the mafiosos were locked up.

      And it's not like these cops are just into big-money crime like drugs, gambling, and vice; they'll work with the local muggers and burglars to tip them about where your valuables are and what days you have the most cash in your till. Saddest place I ever lived.

      Anyway, it's sad how many kids in NJ would like to marry mafia money.

    • Now, with that said, digital modulation, being much closer to a square wave than an analog voice signal, is much richer in HARMONICS than said analog signal.

      This is utter and total nonsense. The modulated RF signal is harmonic and spectrally in accordance by regulation. Digital modulation doesn't cause carrier harmonics (the two are unrelated) and the harmonics from the square wave digital (which cause sidebands or wider bandwidth depending on mode) are of course attenuated at base band before modulation is applied and/or filtered out.

      After all, any energy wasted in "harmonics" is energy that is not available to carry information to the receiver. Digital modem designers (RF or otherwise) have known about this for approximately forever.

      I've lost count of how many times I've heard interference from digital paging transmitters bleeding into ham radio repeaters. The harmonics from the digital modulation mix with the transmitter's carrier, and that of whatever other transmitters happen to be on the same hilltop, and close to the same frequency range. It sounds awful, and it looks even worse on a spectrum analyzer screen.

      Again, this has nothing to do with the DIGITAL nature of the transmitters. Intermodulation is usually not a result of harmonics from the transmitter, but rather harmonics generated in your own receiver - totally independent of modulation mode. And yes, it does look ugly on a spectrum analyzer - whether it is digital or analog.
  • by evilviper ( 135110 ) on Saturday November 02, 2002 @02:38AM (#4582836) Journal
    Insert Joisey-joke here.


    Geena Davis: "Easy, sport. I got myself out of Beirut once, I think I can get out of New Jersey."

    Sam Jackson: "Yeah, well don't be so sure. Others have tried and failed... The entire population, in fact."

  • by LinuxOnHal ( 315199 ) on Saturday November 02, 2002 @03:14AM (#4582896) Homepage
    Digital television won't affect small towns very badly. Many small towns are still on the 460 mHz band, rather than the higher bands that Digital TV will use. Remember, the FCC is clearing out the lower broadcast bands and moving everything up into the UHF and Microwave bands, where police don't do a whole lot of talking.

  • Jersey (Score:2, Funny)

    by magic ( 19621 )
    The irony is that it is impossible to get a decent TV or radio signal in Jersey normally...


    -magic

    • That is actually pretty far from the truth. New Jersey lies smack dab between the largest television market, New York, and the fourth largest, Philadelphia. That gives us some of the best choice of programming in the United States.
  • Wait a minute... I thought the whole point of the FCC was to prevent these kinds of conflicts from happening in the first place, not encourage them by mandating new barely-tested technologies. Oh well, I guess we'll be fine so long as the major media companies get to control a larger slice of the spectrum than they already have.
  • Allocations (Score:5, Informative)

    by rfg ( 163595 ) on Saturday November 02, 2002 @04:01AM (#4583005)

    A lot of innacurate information has been passed around here.

    UHF communication frequencies generally go from 450-470 mHz and were fully populated years ago. What the FCC did is to allocate certain UHF TV channels to communications, in the 470-512 range; ie TV channels (not cable channels) 14-20 for communications use in certain areas. The areas in question are laid out in a plan, so that in some areas a certain channel is used for TV and and in some areas that same channel is used for communications.

    This came about because in a given area you cannot have adjacent TV channels used by TV or they interfere with each other. Also, UHF TV was never really popular with broadcasters and many channels were loped off on the upper end (ch 70-88 as I recall).

    Thus it is perfectly in accordance with the FCC plan to have Channel 20 allocated to TV in Boston and to communications in Southern New Jersy. Up to now, however, channel 20 was never used in Boston, it was empty and now has been allocated to digital TV.

    Analog TV stations must convert to digital by a certain date (2006, but keeps slipping....). During the interim period, the station may transmit Analog on its present channel, and digital on the new channel. This is precisely what WCVB is doing. Eventually the station will be strictly digital on Channel 20 and the Analog VHF transmission will terminate.

    East coast atlantic tropospheric ducting is common and radio hams and others are well aware of it; I am surprised the FCC did not take this into account when they allocated the channels. If I had to speculate, I would say that the FCC will require WCVB to reduce power, use a directional antenna or change channels - which may be tricky. This will be fertile ground for hordes of lawyers.

  • This is actually an issue the other way as well.

    As the FCC forces digital broadcast and begins to sell off the UHF and VHF ranges for communications equipment....what will happen if a TV station is still broadcasting.

    For instance, in San Diego the local Fox affiliate actually has their broadcast tower in Mexico (they can get a permit for a stronger signal there). If a nationwide carrier developes communications equipment uses that part of the spectrum...their equipment won't work in San Diego.

    How will the FCC control 'foreign' signals?

  • The license application for the 8VSB signal had to have gone through an FCC attorney, who would want the engineering reviewed by a consulting engineer. This is partially the fault of the consulting engineer, and mostly the fault of the FCC in not anticipating tropo.

    The irony is in the fact that digital television is supposed to be predicated on the television stations giving up their VHF allocations for other purposes. The other purposes are digital communications for public safety -- police.

    So until the VHF channels are vacated and the equipment manufacturers actually have type-accepted equipment for the new bands, the police in this community are basically screwed.

    Or maybe they need to get a STA (special temporary authorization) and retune their equipment and get a new frequency.
  • ... the radio waves are noisy in joisey?
  • by wowbagger ( 69688 ) on Saturday November 02, 2002 @10:19AM (#4583585) Homepage Journal
    I would RTFA, but the link is broken.

    However, I find this somewhat surprising. Most police band radios operate in the 800MHz trunking band, which is reserved just for that purpose.

    I didn't think the FCC was allowing digital TV anywhere near those frequencies - in fact that is why UHF TV channels 68 and up (IIRC) were taken out of service - to make room for the public service trunking band.

    I would guess that what probably happened was that the station in question was mixing with another signal, and spattering into the police band.

    In all probability, the cops didn't hear what the station was transmitting - Jersey is using Motorola Astro trunking, perhaps even digital mode, so the cops' radios would simply have said "this isn't the signal I was looking for. Move along."

    Does anyone have a link to a cache?

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