practical solutions for miles of ethernet?

Discussion in 'Networking & Security' started by Thuleman, Sep 9, 2008.

  1. Thuleman

    Thuleman [H]ardness Supreme

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    Does anyone have practical experience with deploying Ethernet connectivity outdoors?

    I am looking into a low-tech solution to connect a bunch of temperature probes to the Internet. They are digital temperature sensors, and the way the technology works is that there is a converter from the native protocol to TCP/IP based Ethernet. Each sensor then becomes a node on the network. Each sensor string has some 35 nodes, and there are 12 strings total, spread out over a rather large area.

    To return the signal to a place where it can then be connected to the Internet at large I would need to bridge approximately one mile (longest distance).

    I know the whole thing can be done wireless, but wireless is too complex for this project, especially since the sensors can be powered over the Cat cable (they are ultra-low voltage) and no additional power is available at the sites the sensors are deployed.

    Running a mile of conduit, and some sort of all-weather Cat5e cable would be the ideal solution, except that Cat5e only goes out to 100 meters max. If anyone has any experience on how to deliver cabled Ethernet over longer distances while keeping complexity down, I would appreciate some input.
     
  2. Mister Natural

    Mister Natural 2[H]4U

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  3. vage

    vage 2[H]4U

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    Your probably going to have to look into fiber. What you could do is run fiber the entire length, and then just get a minimic or whatever which makes it cat5. Only thing about doing it that way is I'm pretty sure you can't do power through fiber.
     
  4. SockMan!

    SockMan! 2[H]4U

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    If you need to run fiber cable anyway then you might as well run copper along with it to provide power.
     
  5. vage

    vage 2[H]4U

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    well if I read it right it does REQUIRE power over ethernet, its just a possibility. So you could just run the fiber and get power from where each node is located. But then again I don't know much about the setup so maybe power would have to be run to each node regardless.
     
  6. Thuleman

    Thuleman [H]ardness Supreme

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    Yeah we definitely need to power the sensors, the issue with running a dedicated power cable is the additional cost. In general the cable needs to hold up to operating temperatures down to -40-ish, needs to be protected from creeping moisture, and any other type of issue cables can face. We are looking for a 10-year lifetime on that installation. With those parameters, running an extra few miles (total) of cable to power things would likely become too costly. The sensors work on 5V, I don't have the mA right now, but it's very low in either case.

    I'll have a look at the Black Box. I am also thinking to call the local telco and see what technology/cable they use to deliver DSL (if they use fiber, then only to the local switch, and then copper from there).

    I am not set on Ethernet cable per se, all I need is the Ethernet protocol and 5V out to up to a mile from the origin.
     
  7. Ockie

    Ockie *** Self Proclaimed Storage King ***

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    You will not be able to get ethernet to travel that far with power sources.

    What I would recomend is a fiber network to POE switches which are a little closer placed. There are plenty of all weather enclosures and POE switches out there. From those switches, you can run rugged ethernet to your sensors with poe.

    Your fiber is basically just a long distance hop from switch to switch. You can buy bulk fiber (direct bury) on ebay for pennies on the dollar (you can get a mile or two spool in most cases for less than $1,000).
     
  8. Thuleman

    Thuleman [H]ardness Supreme

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    I was hoping there was a way to avoid running a power line. I figured since any type of voltage drop isn't an issue and since we don't need any bandwidth (one measurement per sensor is taken every 12 hours, that's 4 bytes of data + overhead per sensor every 12 hours), there would be some way to avoid running a power line.

    As you may imagine, the whole thing isn't a "let's hire a consultant and spec this thing out" type of deal. We have some spare equipment, and we did find a purpose for it, now it's just a matter of making it work without to go totally overboard with additional costs.
     
  9. LoStMaTt

    LoStMaTt 2[H]4U

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    If I were the OP I would be researching how seismometers transmit data from their stations to the offices that receive the data.

    A similar setup of data transmission would probably work.