Alternative Frequency Wireless Ethernet Devices?

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."

Comments

Mirrors

[mfos.org]

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

How much bandwith?

[thefatz]

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?

Re:How much bandwith?

[Komodo]

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.

Re:How much bandwith?

[Mignon]

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.

30 feet?

[Neck_of_the_Woods]

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......

Re:30 feet?

[grammar nazi]

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?

Creative Ideas

[the eric conspiracy]

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.

Other requirements:

[Hubert_Shrump]

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.

Use the right frequencies

[anthony_dipierro]

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

Why and where

[WindBourne]

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.

GENRIP

[nesthigh]

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

Modulated light

[Futurepower(R)]

He's right. Modulated light avoids electromagnetic noise.

*strokes cat* la-ser

[awx]

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

Fiber?

[wowbagger]

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.

Re:Fiber?

[wik]

>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!