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Google Building a 100kW Transmitter at Spaceport America (hackaday.com)

Posted by timothy on from the well-where-do-you-keep-yours? dept.

szczys writes: Google is building a 100kW transmitter at Spaceport America. As is becoming the regular source of early info, this comes via an FCC filing in which Google has asked the agency to keep the project secret. The signal strength itself isn't [groundbreaking] until you learn this is a directional antenna. Some of the most powerful FM radio transmitters get to 100kW, but those are omnidirectional. This is a highly focused directional antenna and that makes it sound like a big piece of Google's hushed Broadband Drone program.

40 of 75 comments (clear)

  1. No, HALF a watt. by jeffb+(2.718) · · Score: 5, Informative

    According to TFA, the highly directional antenna gives a peak effective power of 96kW along its lobe, but total radiated power is 500mW -- half a watt. So the comparison to "powerful FM radio transmitters" is kind of silly. In fact, it's even sillier than that, because FM broadcasts (at least here in the US) are around 100MHz, and this transmitter will be in the range of 70-80GHz, with completely different propagation characteristics.

    1. Re:No, HALF a watt. by Anonymous Coward · · Score: 2, Funny

      I was wondering what they were going to do with 100kW through a highly directional antenna, supply satellite TV to Mars?

    2. Re:No, HALF a watt. by Adriax · · Score: 5, Funny

      Google Eye of Sauron.

      --
      I don't suffer from insanity, I enjoy every minute of it!
    3. Re: No, HALF a watt. by bill_mcgonigle · · Score: 4, Funny

      Shush, we're hysterical with misinformation and misunderstanding.

      --
      My God, it's Full of Source!
      OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
    4. Re:No, HALF a watt. by MobyDisk · · Score: 4, Informative

      So we are to believe 96KW raw power results in 500Mw of final output?

      No.

      1. You meant 500mW (milli-watt) not 500Mw (mega-watt).
      2. You have it backwards. 500mW raw power results in 96KW of equivalent omnidirectional output.

      How inefficient is that?

      3. This is not a measure of efficiency.
      Look up EIRP

    5. Re:No, HALF a watt. by Anonymous Coward · · Score: 1

      I'm not sure if you're telling me to google Eye of Sauron or if that's the name of the thing, "Google Eye of Sauron".

    6. Re:No, HALF a watt. by jeffb+(2.718) · · Score: 1

      You seem to be thinking of a different wavelength. We're talking about 80GHz here. I actually get less than 60cm, but that's assuming 100% antenna efficiency.

    7. Re:No, HALF a watt. by subk · · Score: 1

      You're both wrong. EIRP on an omni antenna such as TV or FM is usually about 10:1. I should know, I maintain two TV transmitters and five FM transmitters. Example. One of my rigs produces 1645 watts of RF energy into an antenna with ~9db of gain, which gets me to my EIRP of 15kW.

      --
      Now, if you'll excuse me, I have backups to corrupt.
    8. Re:No, HALF a watt. by fizzup · · Score: 1

      MobiDisk has made the common mistake of referring to an isotropic radiator as an omnidirectional radiator. Omnidirectional does not have the same rigorous definition as isotropic, which has led to your misunderstanding of his comment. If you re-read his comment, replacing "96kW of equivalent omnidirectional output" with something more like "radiated power in the major lobe equivalent to a 96kW isotropic radiator" then you will understand his original intent better.

    9. Re:No, HALF a watt. by subk · · Score: 1

      That's why I kept my comment limited to the omnidirectional radiator realm where I have experience ;-)

      --
      Now, if you'll excuse me, I have backups to corrupt.
  2. What could possibly go wrong? by thsths · · Score: 1

    Fried birds falling from the sky, for example.

    http://deadlinelive.info/2011/...

    1. Re:What could possibly go wrong? by jeffb+(2.718) · · Score: 4, Informative

      You must get really tired of frying the side of your head with your cell phone, then; its maximum transmit power is more than one watt, and if you're holding it to your ear, you're intercepting close to half of that power.

      This isn't a high-power transmitter. This is a low-power, but hyperdirectional transmitter. Think cantenna on steroids.

    2. Re:What could possibly go wrong? by jenningsthecat · · Score: 1

      You must get really tired of frying the side of your head with your cell phone, then.

      In the days of analog-only cellular, I DID (somewhat) fry the side of my head with a cell phone. I was using my boss's (fairly) small hand-held unit - this was shortly before digital cellular came along IIRC. Whenever I used the phone for more than a minute or so, I would get a diffuse itching feeling inside my head near the phone antenna. When I switched sides, the itch moved to the other side, consistently and repeatedly.

      I know, I know, correlation isn't causation, etc, etc, but this was utterly consistent and repeatable at will, and I never felt anything like that itch before using that phone nor after the boss got a new one. Also, I'm an electronics technologist who has spent A LOT of time doing RF work, including repairs of military radar and nav gear, so I'm both experienced with and not paranoid about RF energy.

      --
      'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.
    3. Re:What could possibly go wrong? by jenningsthecat · · Score: 1

      You must get really tired of frying the side of your head with your cell phone, then; its maximum transmit power is more than one watt, and if you're holding it to your ear, you're intercepting close to half of that power.

      These same morons somehow thought it was better to wear an earpiece and keep the "radiation emitting" phone in their pocket or on a holster near their genitals instead.

      If they were wearing a wireless earpiece, then they're probably not morons, and it probably WAS better. The power emitted by the phone in order to reach a cell tower is FAR greater than that emitted by a Bluetooth earpiece that's good for a few tens of feet at most. OTOH, if it was a WIRED earpiece, then it was probably a luck-of-the-draw thing as to how much RF energy was conducted / guided by the earpiece cable to the head.

      --
      'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.
    4. Re:What could possibly go wrong? by jeffb+(2.718) · · Score: 1

      Well, I was replying to a post about "fried birds falling from the sky", but sure, go ahead and point to a study that shows higher increases in cancer rate with lower levels of radiation -- it's a miracle life ever arose on Earth, apparently, what with our exposure to the homeopathic death aura of cosmic background microwave radiation.

      As far as actual risk, you're more likely to be killed by flying goalposts, at least in this thread, apparently.

    5. Re:What could possibly go wrong? by jenningsthecat · · Score: 1

      There's plenty of evidence that microwave radiation at the level of a cell phone increases cancer risk. Here's one repeated, peer-reviewed study: http://microwavenews.com/news-...

      I'm not willing to pay for a copy of the research paper, (fuck Elsevier), but I'd like to read it. It's so easy to play games with numbers in order to arrive at 'statistical significance'. All too often a 'smoking gun' turns out to be the combination of a replica firearm and a puff of mist. I'm not saying there ISN'T a causal link between RF exposure and various kinds of biological harm; I'm only saying that it will take more than third-hand conclusions about a scientific study to convince me. (This in spite of my posting above regarding having felt the effect of cell phone radiation on my own head).

      --
      'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.
    6. Re:What could possibly go wrong? by torkus · · Score: 1

      I'm not about to pay 42 bucks to read the study so I can't speak to it directly. With that said, there's been numerous OTHER studies which have entirely refuted these types of claims.

      There's also plenty of evidence that god exists depending on where you set the bar for 'evidence.'

      --
      You can get rich if you own a politician, but you have to be rich to buy one in the first place.
    7. Re:What could possibly go wrong? by torkus · · Score: 1

      Not to play grammar nazi ... but you're interSECTING about half of the radiated power. You're certainly not interCEPTING half of it.

      This assumes cell phones use omni-directional antennas which I rather expect is the case. If your body intercepted half the radiated power then holding the phone to your ear would result in a lot of dropped calls in mediocre coverage areas.

      --
      You can get rich if you own a politician, but you have to be rich to buy one in the first place.
    8. Re:What could possibly go wrong? by JazzLad · · Score: 1
      I think you missed this part ... :)

      near their genitals instead.

      --
      "If you have nothing to hide, you have nothing to fear." - Every fascist, ever
    9. Re:What could possibly go wrong? by jeffb+(2.718) · · Score: 1

      Eh, maybe. I guess I was thinking of "intercept" in the sense of "x-intercept" on a graph. You're in the way of about half of the radiation, but you're absorbing only a tiny fraction of that. As you say, phones wouldn't work well if it were otherwise.

  3. Tinfoil hat by 110010001000 · · Score: 5, Funny

    And you guys made fun of my tinfoil hat! Who is laughing now???

    1. Re:Tinfoil hat by mitcheli · · Score: 1

      This talk of solar power drones providing Internet Access does sound... tin foil like... doesn't it. Seem to recall a project called Google Street View where they came up with the idea of mounting cameras on cars and driving around every road in the world taking pictures. Also found it interesting that all the wifi data was war driven at the same time, not just the GPS coordinates of everyone's home routers, but captures of the traffic as well. So I guess my question is, while it's nice to have that broad band internet beamed from a few hundred feet up, what else is the drone doing? Seems somewhat voyeuristic to me.

      --
      Select from tblFriends where interesting >= 4;
    2. Re:Tinfoil hat by ThatsNotPudding · · Score: 2

      And you guys made fun of my tinfoil hat! Who is laughing now???

      Everyone not wearing inductive wrap that locks-in the cooking juices.

  4. Just a bit of editing, please by wonkey_monkey · · Score: 3, Informative

    As is becoming the regular source of early info

    What?

    The signal strength itself isn't [groundbreaking]

    Not as [groundbreaking] as your bizarre use of [square brackets], certainly.

    --
    systemd is Roko's Basilisk.
    1. Re:Just a bit of editing, please by Anonymous Coward · · Score: 1

      Is {this} better?

    2. Re:Just a bit of editing, please by Anonymous Coward · · Score: 1

      Square brackets are used by hackaday to highlight people's names/handles, so there is no confusion.

      So clearly, in this case, [groundbreaking] is just someone's name.

    3. Re:Just a bit of editing, please by Anonymous Coward · · Score: 1

      I suppose it was a quote. Then the use of the brackets would be quite customary. They are used to indicate a word that originally wasn't in a quoted statement, but was implied by context and added to the quote to restore the meaning of the statement. For example, see the Harvard style guide for quotations for reference.

    4. Re:Just a bit of editing, please by szczys · · Score: 2

      You're right that we use square brackets on Hackaday to indicate usernames. However, in this case I think I left out a word in my submission and the /. editors added it using the square brackets to indicate the change.

  5. im sure the discussion was touchy. by nimbius · · Score: 1

    Google: we want a 100kw FM directional station.
    FCC: is this for your internet by drone idea? ooh! what kind of futuristic drones are you working on!!
    Google: [furiously crumples plans for directional lynard skynard as a service broadcast] YES! uh, you betcha it is!

    --
    Good people go to bed earlier.
  6. Anytime Now by twmcneil · · Score: 1
    The second link above points to a /. entry from almost a year ago entitled:

    Google's Solar-Drone Internet Tests About To Take Off

    "About to"?

    What is this some kind of Duke Nukem thingy?

    --
    "The ferrets, they're every where I tell you!"
    1. Re:Anytime Now by pla · · Score: 1

      "About to"? What is this some kind of Duke Nukem thingy?

      Google doesn't exactly have a reputation for vaporware announcements... More like the exact opposite - They release fairly mature services at the drop of a hat. And sure, many of those fail, but enough don't that we've come to take Google for granted as just shy of "infrastructure" in terms of their importance to the proper functioning of the internet.

  7. any old-timers left?! by Thud457 · · Score: 1

    I wish I was in Tijuana, eating bar-be-qued iguana...

    --

    the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff

  8. reminds me of the original Tesla Tower by peter303 · · Score: 1

    He built in New York and Colorado Springs. https://en.wikipedia.org/wiki/...

    1. Re:reminds me of the original Tesla Tower by RubberDogBone · · Score: 1

      He built in New York and Colorado Springs.

      https://en.wikipedia.org/wiki/...

      Not even remotely the same purpose, same frequency or even the same construction or appearance.

      But other than that, sure, it's identical.

      .

      --
      Sig for hire.
  9. More like 100mW by EmagGeek · · Score: 1

    It's probably more like 100mW with a 2 meter dish that gives 60dBi of gain at 80GHz.

    1. Re:More like 100mW by yodleboy · · Score: 1

      "It's probably more like 100mW with a 2 meter dish that gives 60dBi of gain at 80GHz."

      can i have that again in proper units such as libraries of congress or blue whales?

    2. Re:More like 100mW by EmagGeek · · Score: 1

      It's probably more like 1/15000th of a microwave oven with a volkswagen-sized dish that makes the signal ONE MILLION TIMES STRONGER when the signal is going SOOOOOOOPER FAST.

  10. Re:keep secret? by quonsar · · Score: 1

    no. RTFA. more like the output of a GI Joe walkie talkie.

    --

    Sacred cows make the best burgers.

  11. Broadcast power by dfsmith · · Score: 1

    Some of the most powerful FM radio transmitters get to 100kW

    The Sutro Tower (San Francisco) has a couple of stations transmitting at 5MW. See this chart. Sutro is by no means the "most powerful" tower, either, at only 24MW ERP.

  12. 100 kW ERP is commonplace - My laser pointer... by n6gn · · Score: 1

    ERP is Effective Radiated Power. In the direction of maximum beam of my laser pointer, I get a spot on the order of 1 " in diameter 200' away. This means that most of the 5 milliwatts the laser puts out is contained in a spot of on the order of one square inch. This intensity is brought about by the columnation or directivity of the laser itself. It's a puny 5 milliwatt transmitter with a high gain antenna. In order to get the same intensity from an isotropic antenna (one that spews equally in all directions) rather than a directive one, I'd need to increase the power by the ratio of 4*PI*(200 feet*12 inches/foot) ^2. That's how many square inches are in a sphere with radius 200'. That's almost 80 dB (a hundred million times) change of directivity. BTW directivity is the same as antenna gain if the antenna is well matched and not lossy. 80 dB above 7 dBm ( 5 mW) is +87 dBm or +57 dBW That's HALF A MILLION watts! But this is not "cooking power". Energy is conserved, it's still only a 5 milliwatt, Class III laser and this ERP number is only a measure of what transmit power would be necessary if there weren't any antenna gain. All this alarm about ERP is about not understanding what the terms mean. ERP is transmitter power + antenna gain, not real power. The actual transmitter is something like 24 watts, roughly the same as one segment antenna of a cell site. The system has high ERP because it's at millimeter where the antenna has a lot of gain. This whole thread is alarm about nothing...