Alternative Frequency Wireless Ethernet Devices? 46
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."
Mirrors (Score:4, Informative)
Modulated light (Score:3, Informative)
Re:Modulated light (Score:2, Interesting)
Re:Modulated light (Score:1)
Re:Modulated light (Score:2)
Slept through Physics class, didn't you?
line of sight (Score:1)
How much bandwith? (Score:3, Informative)
Re:How much bandwith? (Score:2)
Use the right frequencies (Score:4, Informative)
Re:How much bandwith? (Score:5, Funny)
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.
Re:How much bandwith? (Score:2)
Re:How much bandwith? (Score:2)
~GoRK
Re:How much bandwith? (Score:3, Informative)
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? (Score:1)
if you abide by the power output and antenea hight you can use these channels for anything you want, except any encription method used is succeptable to hacks as it is LEGAL to listen and use any information broadcast on CB channels because that information is public domain while it is in transmission. if you want to use this for a network, get some really good encription.
Re:How much bandwith? (Score:1)
Plug that ethernet card right into a pigs ass and see what happens!!! Seriously tho, isn't this being done using packet radio?
30 feet? (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......
Re:30 feet? (Score:3, Funny)
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?
Re:30 feet? (Score:2, Funny)
> 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!
What kind of area? (Score:2)
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.
Creative Ideas (Score:4, Insightful)
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.
Re:Creative Ideas (Score:1)
Incidentally... a nice feature of fiber networking is that it doesn't give a rats ass about electric fields or potentials. Can you just drop or hang fiber? That will make you all but bulletproof, with very large capacity.
Other requirements: (Score:4, Funny)
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.
wireless packet program (Score:2)
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.
Why and where (Score:4, Interesting)
GENRIP (Score:5, Informative)
next
Boy scout training comes in handy here (Score:2)
900MHz (Score:1)
Eh. I'm not an expert, but isn't 900MHz the base frequency of (older) GSM phones? ' Guess telcos won't be very enthousiastic about the idea of sharing it...
Re:900MHz (Score:1)
I'm the generic ip over radio seems to be the best idea so far. or maybe the interns.
Re:900MHz (Score:2, Informative)
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.
Optical (Score:1)
If you have high EMI in your environment, copper cable and radio will have much trouble, no matter at which frequency they work. You need to use either sound or light. Sound (ultrasonic) is very rare in networks (at least I do not no any solution for IP over ultrasonic), light leaves two possible solutions. IrDA (at any speed) and some mirrors, like someone else already proposed, or optical fibre. If you need to move your devices, you have to use IrDA, maybe with mirrors at the ceiling or other optical tricks (like lenses). Otherwise, just stick with plain old ethernet over fibre.
*strokes cat* la-ser (Score:3, Interesting)
License (Score:2)
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
Fiber? (Score:3, Informative)
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? (Score:3, Informative)
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!
Look for vendors in bad EMF markets.. (Score:2)
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.
Amateur Radio (Score:1)
-Tom
Different antenna (Score:1)
-Tom
Maybe... (Score:1, Funny)
I heard those worked really worked well in ancient times.
GENRIP (Score:1)
AVIAN CARRIER PROTOCOL!!! (Score:1)
Consider RFC1149 (Score:2)
It isn't ethernet, but what the heck:
A little birdseed goes a long way....