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Alternative Frequency Wireless Ethernet Devices?

Posted by Cliff on from the mutant-devices dept.

rtgree01 asks: "Do Slashdot readers know of any wireless ethernet devices that are not 900 MHz, 2.4GHz, or 5GHz. This is for a project that will be in an extremely harsh EMI area (thousands of V/m at those frequencies). Also, to make things even more impossible, line of sight is not available, even though the range for this system should be 30 feet max. Some of you might suggest to stick with a standard wired solution, but that is not optimal at all. Any suggestions would be greatly appreciated."

28 of 46 comments (clear)

  1. Mirrors by mfos.org · · Score: 4, Informative

    I don't know the exact setup you have, but IR with mirrors might work

  2. How much bandwith? by thefatz · · Score: 3, Informative

    How much data do you plan on sending? Data over ham might work. You might be able to find some 19.2kbps wireless modems that work together. Any Ideas?

    --
    http://www.freebsd.org
    1. Re:How much bandwith? by shaitand · · Score: 2

      not if this environment is commercial, that would be illegal.

    2. Re:How much bandwith? by GoRK · · Score: 2

      Um, you know it's illegal to transmit encrypted data over amateur radio, right? Kind of shoots any security out of the water, which is probably a bad idea for his network..

      ~GoRK

    3. Re:How much bandwith? by Komodo · · Score: 3, Informative

      I don't think it's actually illegal to transmit encrypted data , but you have to keep a copy of the transmitted data (in the clear) for inspection by certain parties, definitely including the FCC.

      What makes it illegal is that it's abusing a part of the spectrum that's reserved and licensed for a particular type of operations (amateur radio). You need to be licensed, and the terms of the license prohibit commercial use - there's very specific rules about that.

    4. Re:How much bandwith? by Mignon · · Score: 5, Funny
      not if this environment is commercial, that would be illegal.

      He wasn't talking about ham radio, he was talking about training pot-bellied pigs to carry the data back and forth. They're very smart, you know.

    5. Re:How much bandwith? by shaitand · · Score: 2

      well damn, why didn't I think of that?

  3. 30 feet? by Neck_of_the_Woods · · Score: 5, Funny



    30 feet that is it? Hell use sneaker net and pay a intern 5.25 and hour to run the data back and forth.

    Get a marketing intern for 10baset, a business intern for 100baseT, and a CS intern for 1000baseT. Keep in mind for the 100/1000 you going to need 2 interns for the full duplex.

    If you want to figure out what is going on with your workers just pick up one of the tri delta girls and set her to permiscous mode......

    --
    Neck_of_the_Woods
    #/usr/local/surf/glassy/overhead
    1. Re:30 feet? by grammar+nazi · · Score: 3, Funny
      Such a system is capable of high bandwidth, but the latency sucks. Especially during lunch time and afternoon break time.

      Tri-Delta girls aren't particularly good girls with regards to networks. Remember that 2 out of 3 go down (an classic joke refering to their logo). Do you really want a 66% system failure rate with your network?

      --

      Keeping /. free of grammatical errors for ~5 years.
    2. Re:30 feet? by Zerth · · Score: 2, Funny

      > Remember that 2 out of 3 go down (an classic joke
      > refering to their logo). Do you really want a 66%
      > system failure rate with your network?

      I dunno about you, but that statistic sounds like a 66% success rate to me:) Your latency is shot already, who cares if most of the packets take another 3 minutes to get there, they will be very happy packets and eager to be retransmitted!

  4. What kind of area? by duffbeer703 · · Score: 2

    Any kind of standard high-speed networking will not function in a high EMI area -- cabled or uncabled.

    I think the military uses a semi peer-to-peer wireless network between armored vehicles and some helicoptors. It is some sort of spread-spectrum technology that violates FCC rules and costs millions of dollars.

    If you cannot run shielded cable or fiber optics, you need to redesign your facility, period.

    --
    Conformity is the jailer of freedom and enemy of growth. -JFK
  5. Creative Ideas by the+eric+conspiracy · · Score: 4, Insightful

    High EMI, mmmm.

    Since line of site and wires seem to be out, maybe more creative ideas are needed. Since you don't say what the data transfer rate needs to be, I'll assume it's not high.

    For low rates perhaps sound pulses would work. This would bring meaning back to the term "ping".

    Another possibility would be paper tape. A pair of writers/readers with the tape running between them would be immune to EMI, and the tapes go around corners nicely.

    Ham radio operators have been sending TCP via radio at all frequencies in the electromagnetic spectrum for many years. While you say that the common frequencies are no good due to EMI, how about elsewhere?

    Another possibility is a hybrid system; wires where they work well, optical where EMI is high might work well.

  6. Other requirements: by Hubert_Shrump · · Score: 4, Funny

    It must be Open Source.

    It must look pretty.

    It can't be composed of matter.

    It can't have been thought of by a carbon-based lifeform.

    It must call me 'Capt. Studjammer' or at least 'Sir Booth Studdington'.

    Pancakes!

    24/7 always-on paradigm outside the box proactive functionality.

    --
    Keep your packets off my GNU/Girlfriend!
  7. wireless packet program by man_ls · · Score: 2

    Posted on Slashdot earlier, there is a program for Linux that will turn any radio attached to a serial port on your computer into an IP-addressable device.

    Your network's operating frequency would only be limited by the hardware in the radio, and of course the speed would be limited by the serial port, which is IIRC about 256kbps.

    Plenty fast for a "logic" connection, such as syncing two systems or for IPC between them, but transferring large quantities of data is going to get long.

  8. Use the right frequencies by anthony_dipierro · · Score: 4, Informative

    You could use MURS along with a ham rig. Or even better if you have the time, use a licensed frequency.

  9. Why and where by WindBourne · · Score: 4, Interesting

    I am curious what environment that you need this at where you u have large amounts of voltage and signal, yet do not have control of the area? Off hand, this makes no sense unless this is needed to get around something that you are not supposed to be in. The implication is that you have a fence with high voltage and windowless wall to communicate through, like a prison. Otherwise, I suggest if you have permission/autharization, then use fiber (30 ft) or use laser.

    --
    I prefer the "u" in honour as it seems to be missing these days.
  10. GENRIP by nesthigh · · Score: 5, Informative

    Depending on the amount of data you need to transmit.. GENRIP, GENeric Radio IP, based on STRIP , may work for you. As discussed here before, it basically extends IP over any serialized radio. So, you can choose your own frequency and power.

    next

  11. Modulated light by Futurepower(R) · · Score: 3, Informative

    He's right. Modulated light avoids electromagnetic noise.

    1. Re:Modulated light by Anonymous Coward · · Score: 2, Interesting

      Not if the e.m. noise is at the frequency of the light. :-)

    2. Re:Modulated light by unitron · · Score: 2
      "Anyway, light is a physical thing, it is not radiation..."

      Slept through Physics class, didn't you?

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

  12. Boy scout training comes in handy here by quintessent · · Score: 2

    I was going to say mirrors and morse code, but without line of sight, that's out. Otherwise, smoke signals should do the trick. Do you have any specific bandwidth or latency requirements?

    --
    Donate background CPU time to fight cancer.
  13. *strokes cat* la-ser by awx · · Score: 3, Interesting

    Lasers modulated by the output from an ethernet port or serial port with PPP, redirected with mirrors?

    --
    Feel that power? That's mah MOUSING FINGER
  14. Re:900MHz by Koos+Baster · · Score: 2, Informative

    Checked that. Europe uses 900, 1800 and 1900Mhz (a triband phone can use all of them).

    Slightly off topic; the 900 Mhz appears to use more energy, so you're probably best off with higher frequencies. This may be a reason some telcos have already decided to ditch the older 900Mhz frequency in favour of the others.

  15. License by GoRK · · Score: 2

    If frequency is your only problem, then you need to figure out what frequencies are clean, then get a license to use a clean frequency and the corresponding equipment to go with it. Alvarion has a lot of stuff available for use at 3-4GHz, and there are other companies that have UHF stuff between 300-800MHz.

    Your other option is to put hook standard equipment up to modulators that will change the frequency. I have worked with devices that double the frequency of 2.4ghz devices to 5.8ghz for use in areas of 2.4 congestion for wireless isp's. There are bound to be other such devices out there.

    ~GoRK

  16. Fiber? by wowbagger · · Score: 3, Informative

    It sounds like this guy needs to communicate to some device that is at a different potential than the rest of the system.

    Have you considered using fiber? High bandwidth, pretty much immune to RF interference, high voltage isolation.

    However, if the target is moving around (some sort of industrial machine, perhaps?) this might not work.

    That's the problem with a lot of Ask Slashdots - the person asking really cannot give a lot of information about his needs, so we cannot weed out suggestions that won't work.

    --
    www.eFax.com are spammers
    1. Re:Fiber? by wik · · Score: 3, Informative

      >That's the problem with a lot of Ask Slashdots - the person asking really cannot give a lot of information about his needs, so we cannot weed out suggestions that won't work.

      Nor will s/he give information about which frequencies *are* good. If a clue isn't given, expect plenty of useless answers. In addition, there is no justification for why a wired connection isn't optimal (and how "optimal" is defined in this situation). It almost seems as if this person doesn't want an answer!

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  17. Look for vendors in bad EMF markets.. by nurb432 · · Score: 2

    Have you looked into contacting companies that make other data equipment for that sort of environment?

    Companies like Allen Bradley, Omron.. etc..

    They deal with high EMF areas all the time in manufacturing plants..

    So even if they DONT have a wireless solution, they have been asked, and prolly know of one.

    --
    ---- Booth was a patriot ----
  18. Consider RFC1149 by divide+overflow · · Score: 2

    It isn't ethernet, but what the heck:
    A Standard for the Transmission of IP Datagrams on Avian Carriers
    A little birdseed goes a long way....