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Communications United States Wireless Networking Technology

Old AM Broadcast Towers Get a New Life 126

Esther Schindler shares an article from Hewlett Packard Enterprise: Video may have killed the radio star, but other media certainly make old AM radio towers superfluous... maybe. "As once-loyal listeners tune away, most AM stations are barely holding onto life, slashing staff and budgets as deeply as they can while struggling to find a return to profitability," reports HPE. "Once upon a time, having a broadcast license of any kind was like having a permit to print money. In today's world, that's no longer true." But, with some 10,000 AM broadcast towers in the United States stretching high into the sky, there may be an opportunity for wireless carriers who don't want to argue with community opposition from neighborhoods where residents don't want yet another cell tower. The amount of money an AM station owner can pocket by sharing its tower with a wireless partner varies widely, depending on the tower's location, height, and several other factors. But it's certainly more income -- and a way to keep "old" technology from becoming obsolete. "Using an AM tower, which has very often been in place for many years, avoids many zoning and other permitting issues, versus going in and creating a new site for a tower," Behr explains. He says local residents, businesses, and officials rarely complain about an AM broadcast tower that suddenly begins serving as a cell site. "That tower was there before they were, and it doesn't bother them," Lawrence Behr, CEO of Greenville, North Carolina-based LBA Group, says. "Hanging a few things on it is rarely controversial, so that's a real good thing for AMs."
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Old AM Broadcast Towers Get a New Life

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  • by Anonymous Coward

    Please please please think of the children and all the cancer this is going to cause!

    Funny note: I have an account on nextdoor. Someone's first post was "I just found out about this tower that was approved for installation (before I moved into the neighborhood). How can I stop it?" So apparently, people seem to believe that they should get retroactive say in communities now. It that or a competing carrier trying to stir up trouble. In the meantime, I get one bar in my Washington DC suburb.

    • Fortunately these crackpots are rarely in a position where they can take on a multi-billion heavy corporation. It's not that trivial to get rid of idiots in many other areas.

    • I live in an area with a regional airport. It's not something you'd be likely to miss. Yet I recall a news story (from about 20 years ago) where someone moved into the neighborhood and THEN decided that the airport should be limited (no flights after 9pm or whatever) or shut down. It always astonishes me when folks do that.
  • Radiation (Score:4, Interesting)

    by dwywit ( 1109409 ) on Friday April 27, 2018 @07:12AM (#56512403)

    Honest question - isn't it necessary to de-energise the transmitter before technicians can climb the tower to install or maintain hardware? Presumably it happens in the graveyard shift. The ERP right at the tower must be quite high.

    • by DRJlaw ( 946416 )

      Honest question - isn't it necessary to de-energise the transmitter before technicians can climb the tower to install or maintain hardware? Presumably it happens in the graveyard shift. The ERP right at the tower must be quite high.

      You can be on the tower, or you can be on the ground, but you can't be on both. It's not the potential that kills, it's becoming a circuit path. Birds roosting on power distribution lines, which as a general rule are not insulated, don't die due to that fact.

      • Re:Radiation (Score:4, Informative)

        by Known Nutter ( 988758 ) on Friday April 27, 2018 @08:06AM (#56512601)

        You can be on the tower, or you can be on the ground, but you can't be on both. It's not the potential that kills, it's becoming a circuit path. Birds roosting on power distribution lines, which as a general rule are not insulated, don't die due to that fact.

        That's not how any of this works.

        First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

        The parent poster was concerned with worker safety when exposed to radio frequency energy [fcc.gov].

        https://transition.fcc.gov/Bur... [fcc.gov]

        After performing the required calculations and determining it is safe to work at x distance from the transmitter antenna, workers will typically wear a personal RF monitor [lbagroup.com] to measure exposure.

        • Thank you for enlightening the rest of us, and for sharing those links. I will now join that crowd that is allergic to wireless signals; at least now I don't have to worry about cellphone towers(I'll just get one of these gadgets from the LBAgroup)

        • Re:Radiation (Score:5, Informative)

          by DRJlaw ( 946416 ) on Friday April 27, 2018 @08:56AM (#56512801)

          That's not how any of this works.

          First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

          Please, tell me how AM broadcasting works [google.com] (first and last visible paragraphs of section 5.5.5.2). Because for the majority of AM transmission towers you are dead wrong - literallty [ubnt.com].

          "Most AM radio towers are series fed (end fed at the bottom) and have a ceramic insulator at the base. A few smaller ones are shunt fed about 20 feet up the tower and are grounded at the base, and a variation are metal poles grounded and have wires insulated from the pole as vertical radiators."

          Up to 50,000 watts says that the primary concern is electric shock. A secondary concern is RF exposure.

          Try Googling AM radio, maintenance, and "hot tower" before you lecture about areas that you plainly lack experience in.

        • The tower itself generally acts as the antenna radiator, and sits on a big ceramic insulator at the base. The tower is at a high RF voltage in reference to earth ground.

          Attaching auxiliary equipment to an AM tower would be a nightmare because of this fact. everything on the tower would be floating at hundreds/thousands of RF volts above ground. The power into and data out of the equipment would need special decoupling/filtering to keep the RF on the tower and out of the power/data lines. Sensitive electro

        • by DRJlaw ( 946416 )

          Oh, and while I'm at it, the FCC's regulations for transmission facilities are described in OET-65 [fcc.gov], not OET-64, and only apply to transmission frequencies above 300 kHz - and thus do not apply to AM radio.

        • First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

          https://www.youtube.com/watch?... [youtube.com]

        • You can be on the tower, or you can be on the ground, but you can't be on both. It's not the potential that kills, it's becoming a circuit path. Birds roosting on power distribution lines, which as a general rule are not insulated, don't die due to that fact.

          That's not how any of this works.
          First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.
          The parent poster was concerned with worker safety when exposed to radio frequency energy [fcc.gov].
          https://transition.fcc.gov/Bur... [fcc.gov]

          After performing the required calculations and determining it is safe to work at x distance from the transmitter antenna, workers will typically wear a personal RF monitor [lbagroup.com] to measure exposure.

          As others have mentioned, you are pretty wrong here. The vast majority of AM towers are the radiators and the ground is the ground plane. Between them sits a huge isolator which is generally ceramic. If you stand on the ground and touch the tower above the isolator you will get burned or dead.

          This makes colocating on an AM tower a PITA as you can't just run a conductor up the tower without a transformer. There are ways to do it, my favorite being to get power off of the tower lighting circuit to power a

        • AM towers are resonant antennas, isolated from ground, on giant load-bearing glass or ceramic insulators. you haven't seen one. tipoff is the arc rings at the base of at lease one tower leg, two non-connected circles, one to the tower leg, one to a grounding field. the occasional contesting ham radio operator will have a live tower, but everything else is grounded. not AM radio and some specialty systems around the medium wave band.

          if you were to run a vertical antenna isolated from the tower, it would be

          • They are the primary and secondary halves of an "Austin Ring" transformer, which is used to get 120V power onto the tower to run the aircraft marker lights. The design is to reduce capacitance between the primary and secondary far below that of a conventional transformer, so as not to short the RF signal on the tower to ground.

            Flashover spark gaps for lightning protection are also found at the tower base, but usually in the form of a ball gap. They are set to flash over at voltages just a bit higher than

        • by Strider- ( 39683 )

          First, the tower is grounded and at the same potential as earth. The primary concern is not electric shock.

          Not on AM broadcast towers. The tower itself *is* the antenna. It's built with large electrical insulators at their base, and the guy wires are also heavily insulated. At the base, there is a spark gap to discharge any lightning strikes, and the tower itself is connected to the transmitter.

      • Ive seen birds vapourised after landing on the 50kw AM open wire coax at a transmitter. Just a claw left on the centre conductor.
        The base of the big AM towers was usually many amber insulators. A steel capped boot brought too close would arc and burn, seen it happen to a trainee, followed by some olympic level hopping.

    • Honest question - isn't it necessary to de-energise the transmitter before technicians can climb the tower to install or maintain hardware? Presumably it happens in the graveyard shift. The ERP right at the tower must be quite high.

      I used to hear stories of the RF engineers at work who simply took a running jump. Kids these days are getting soft.

  • Mast sharing was done since the '50. In thiss photo you could see two masts sharing AM plus FM plus TV VHF plus TV UHF plus microwave links [mediasuk.org] The AM antenna is the T shaped wire between the masts. I am not surbrised at all that you coluls share services, because there masts are quite costly.
  • Mounting on an AM tower requires decoupling the antenna and transmission line from the AM antenna. The antenna resistance of the tower would have to be remeasured to show this had been accomplished. This would be particularly difficult on a directional station. Perhaps the FCC would relax rules on non directional AM's to reduce these requirements since AM station contours are not so critical any more.
  • by mark_reh ( 2015546 ) on Friday April 27, 2018 @07:59AM (#56512579) Journal

    crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games. Every station broadcasts continuous running advertisements interrupted occasionally by "programming", which is itself mostly advertising. We have a lot of stupid people in the US, but how even they listen to that for more than a few minutes at a time?

    AM broadcast radio is going the same way SW radio (also AM broadcast, except at higher frequencies) did back in the 80s and 90s. The big players give up on it, then the religious nuts take over, then it fades into obscurity.

    • by Terwin ( 412356 )

      Except AM and FM radio are currently doing a lot better than television:
      https://www.washingtontimes.co... [washingtontimes.com]

      AM radio has been pretty steady for a while, and it seems more likely that adding cell antennas to radio towers is just an additional revenue stream.

      If AM radio is dying, it is because of the crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games. ...

      Perhaps because that is what most listeners want?
      As opposed to NPR which could not stay on the air without government subsidies.

      Ever consider that main-stream and 'kook' might not be where you think they are?

      • Re: (Score:2, Interesting)

        by mark_reh ( 2015546 )

        The ridiculous number of commercials on broadcast TV (and cable-only channels) is another big reason for cord-cutting. You can subscribe to commercial free services on-line (Hulu, Netflix, etc.) without having to also pay for 150 channels of commercials you don't have any interest in.

        I know it may be difficult for a "might-makes-right" mentality to grasp, but here's the thing: numbers may make them the mainstream, but it doesn't make them less kooky. Intelligence, like beauty, is a rare thing among humans

        • The Electoral College failed to fulfill its purpose in the last election.

          It fulfilled it's purpose precisely, which is to dilute the electoral power of population centers and result in a true United States, not just "Big Cities and their Farming Colonies".

          Same purpose as two senators per state.

          Now, you may not like that purpose. But it's literally the purpose of the electoral college.

      • Our public broadcasting in the US are cooked, gone, done. I tried to watch PBS News Hour it a few weeks ago. I used to watch every night about ten+ years ago--before the digital switch mostly. They are not replacing the anchors and they are extremely biased--I was shocked. There is no reason to fund them anymore. They are essentially mainstream media.

    • crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games. Every station broadcasts continuous running advertisements interrupted occasionally by "programming", which is itself mostly advertising. We have a lot of stupid people in the US, but how even they listen to that for more than a few minutes at a time?

      AM radio was essentially saved by one particular "right wing ranter" who launched a phenomenally successful three hour show in 1988. Like him or hate him, it's dishonest to claim that he had anything other than a positive effect on AM radio, business-wise.

      As for the rest, you are confusing cause and effect. Music, the 800 pound gorilla of radio, left for FM, for obvious reasons. Making AM affordable for more niche content. Again, AM simply would have died for real decades ago without that content coming i

    • by havana9 ( 101033 )

      crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games.

      I think this is an US-centric view. In Europe, due the fact almost all AM radios are public, normally are a simulcast of FM or satellite broadcasting. The programming is almost news or sports , but sometimes there's a music programme.
      The AM killer is unfortunately the invasion of cheap switching power supplies and cheap digital electronics that pollutes the spectrum used for AM stations, making the listening of them, especially into the cities. Finding also a decent AM receiver is difficult these days, and

      • The AM killer is unfortunately the invasion of cheap switching power supplies and cheap digital electronics that pollutes the spectrum used for AM stations

        In my city it's the overhead trolley wires that power the buses. Driving under them makes AM un-listenable in my car - And if you pull up behind an electric bus connected to the wires, well forget it - It's over to FM.

        http://www.curbsideclassic.com... [curbsideclassic.com]

        If memory serves, the trolleybus wires are 600 volts DC.

        • Widespread use of CFL and LED lighting (with the cheap power supplies and ballasts) aren't helping the RFI front, either.

          And the interference is even worse on some shortwave bands than the AM broadcast band...

    • The entire reason the right is on AM radio is that they were banished there by the left wing media. They made sure all the good media that reaches millions were purified of dissenting thoughts. The right was marginalized all the way back to AM radio, a medium that hasn't been relevant since the 70s. And it appears that isn't even good enough, eh? Banish them from AM as well? Jesus.
      • Good point. Mainstream media is the "they should make a law" crowd where every answer to every issue is crafting a law in Washington DC. Corporate giants love that shit...they want everyone looking to government which they control...usually...save for the Trump fiasco.

    • Yeah. Remember listening to music on the AM Radio [youtube.com]?

    • by kenh ( 9056 )

      ...crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games.

      Remember when the Left decided to beat the Right at their own game [wikipedia.org]? That was fun, I love to watch the movie that tracked the rise and fall of Air America, Left of the Dial [amazon.com].

    • by tlhIngan ( 30335 )

      crap that is broadcast on it all day, every day. Right wing political rants, conspiracy theorists, and religious kooks have taken over all the space between the baseball games. Every station broadcasts continuous running advertisements interrupted occasionally by "programming", which is itself mostly advertising. We have a lot of stupid people in the US, but how even they listen to that for more than a few minutes at a time?

      AM broadcast radio is going the same way SW radio (also AM broadcast, except at high

      • where you find non-commercial and educational stations (below 92 MHz).

        There are 2 nice college stations (WFMU and WFUV) that come in fairly well near me.

        For lefty talk, there was always Pacifica/WBAI, but they ran off the rails with an internal coup almost 20 years ago. Now they air all kinds of magic cancer cure scams and some fairly regressive Mugabe-worshipping talk show hosts.

  • by Anonymous Coward

    AM radio is dying because there is too much electrical noise to make it a fun listening experience, unless you like pops, cracks, whining noises with your audio.

    • I predict that the hipster-doofusses who are reviving vinyl records (you know, neck beards and man-buns) will eventually catch on to AM radio and it, too, will become a thing again - for a little while, until they discover CDs and FM radio...

    • HD radio would have solved it, but the licensing for the proprietary codecs is way too high. I've heard HD radio on the AM band. It sounds fairly good - somewhere between analog FM and 128Kbps MP3. Both way better than analog AM.

  • I love the various attempts at making cell towers look like trees. Some blend in very well. Others are very obviously fake, especially when there are no other trees around. Still, they look better than naked metal.
    • In the midwest where I live, I have noticed an increasing trend to hide cellphone towers inside modern church belltowers. This probably helps to offset the cost of building the church, because the cellphone carriers have to pay for upkeep, and maybe purchase the land.

      I have never attended any of these churches, but I comically imagine that "Today's sermon brought to you by Sprint. GOD, can you hear me now?".
      • Today's sermon brought to you by Sprint. GOD, can you hear me now?

        That's Verizon's thing. Sprint will just be advertising how your brand of Christianity is within 1% of the other denominations.

  • by Anonymous Coward

    I went past an AM tower and had explosive diarrhea. Obviously it wasn't from eating at Chipotle. It had to be the tower!

  • by jenningsthecat ( 1525947 ) on Friday April 27, 2018 @09:20AM (#56512933)

    The AM broadcast-band, (and its close relatives, the short wave bands), allow for long-distance radio communications. Even in the daytime the coverage is pretty good; but at night, when the ionosphere allows for 'running skip', its reach is truly impressive. There may be times in the future when that's crucial for reaching people over very large geographical areas. We really need to backstop our wired networks with wireless analog broadcast capability. It can reach anybody who has a $5 pocket radio, it continues to work even when all you have is batteries or generators and a tower, and it doesn't rely on hard links that can easily be broken. And it's already there, fer chrissake - all we have to do is maintain it.

  • Should the desperation of radio not be a lesson for the modern marketing shills like Google and Facebook? It's a terrible model to build an empire not on providing products and services but on selling out to marketing. It is the most parasitic of American ways.

    This is where Microsoft and Apple differ. They provide the populous with genuine products and services. Too bad the unwashed masses are poor judges of merit to exist.
  • Some of the towers I've seen are not capable of handing an offset weight like tower man toting tools and gear. The amount of corrosion on the tower will force a judgement call by the techs on if it will be scaleable or no. There's not going to be palms greased by the green stuff as incentive, this is life or death.

    A 30 year old tower went down last year during Harvey. It was a 200 footer, rated for 160-180 MPH winds. Harvey sported 180 and it came down in a pile of pipes and cables. Another 175 footer

  • Slightly off-topic, but the thought has occurred to me more than once: They keep having to put up more and more cell towers, festooned with as many antennas as it can hold, to meet consumer demand -- and apparently it's not enough, because if there's an emergency and everyone is trying to dial out simultaneously, the system gets overloaded and calls don't go through. Cellular base stations can only support so many simultaneous calls at once. When and where is the point of critical mass going to occur? Where
    • by jwhyche ( 6192 )

      When and where is the point of critical mass going to occur? Where I'm going with this is: What's the technology that's going to ultimately have to be developed to replace this technology?

      It's already here. It's called voice over wifi and is exactly what it sounds like. When your phone is on wifi all calls are routed through the wifi connection. My S7 had it and my S8 has it. I think most iPhones have it now.

      On my S7 it wasn't quite right. I could move from a wifi call to cell tower and it would ether drop the call or there would be a loud hiss during the conversion. With the S8 that issue is gone. Now when I move from wifi to cell there might be a little click when I do.

      With tho

      • I hear you, but that sounds like more of a band-aid than it does an actual cure; we're still talking about many many antennas and access points all over the place, even worse than cellular because WiFi has such a shorter distance.
        • by jwhyche ( 6192 )

          While I agree with you that it is a band-aid its not as bad as you make it out to be. Depending on where live. Where I live virtually every business has a public Wifi and wifi hotspots are easy to hide.

          Two years ago I worked in the cell phone industry. The technology that you are looking for is VoLTE. Which stands for voice of lte. Basally, they plan to remove the phone network and route all calls over the LTE data stream. I believe they are already doing this in some areas.

          VoLTE will mean less a

  • The *problem* for using AM broadcast towers for cell phones and line of sight RF links is they are usually not located in the right places and are usually taken down when the station goes bust unless they are under 200' tall.

    AM is pretty low frequency and this means that you didn't need line of sight to the tower to receive it. During the day, propagation to the local area was almost assured, even with a modest antenna and ground plane. You didn't need a tall tower or an elevated location, you just need

  • 1) AM Transmission towers, if active, will have tens of thousands of watts of RF energy coursing through them while the station is transmitting - I suspect that will have a negative impact on the performance of the data systems you want to locate on the tower.

    2) AM Transmission towers are hundreds of feet tall, and while properly zoned and permitted, are designed merely to support themselves - they are not designed or installed to support hundreds of pounds of radio equipment and antennas attached to the to

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