Underground to Surface communication

[TOMMYO]

I have an application the requires Ethernet communication from underground to the surface up to 7km. The underground device is restricted to 10base5, 10base-T or 10base2. This device will reside in an industrial PLC and needs to have some link to the surface to allow workers to monitor the integrity of the equipment. Along the path there will be high voltage powerlines drawing power up in the mega watts. Any suggestions ?

[esteban]

7KM underground !!! I don't think you can use a wireless link for this. I think you may be able to use a fiber optic conection. Anyway if some how you have line of sight from the botton to the top you can use a pair of parabolic grid antennas with a cisco aironet 1200.

Esteban

[color_copier]

7km is pretty far, and I don't think you will get a good connection with Ethernet due to the high voltage power lines, they will cause interference with Ethernet.
I would suggest fiber and probably some repeaters/amplifiers.

But if you HAVE to go with Ethernet based I'd suggest some major sheilding on the wires. I'd imagine you'd need repeaters/amps as well to extend the signal further.

I am not very knowledgable in this area, but this might give someone some ideas or get you started on research.

[JimGeier]

If we're assuming this entire range is through building structures and earth, then 802.11 technology won't work unless you're able to place some repeaters along the path. The problem with repeaters, however, is that they introduce delays. If your device doesn't need high data rates, then you might consider ultra low frequency RF devices (if wireless is the only practical way to go). I'm not very familiar with that part of the spectrum, though.