WiFi, Light Bulbs, And The FCC

JFMulder writes "According to Cringely, 802.11 WiFi wireless networking is going to get in lot of troubles when Fushion Lightning starts marketting low-power light blubs which causes interferences with Wifi signals. Read about it at I, Cringely. Supposedly the new kind of light bulb is a real electricity saver and can wreck havoc to wireless networks in a half a mile radius. So what would you prefer? Wireless networks or low cost light bulbs all around the country to save more and more on electricity?" Update: 06/13 03:52 GMT by M : Cringely confused the FHSS-or-DSSS 802.11 standard with the DSSS-only 802.11b standard, but the general warning about the potential for interference is certainly troubling.

Not a problem, an opportunity!

[NewtonsLaw]

Well the answer appears very simple to me.

If these lightbulbs are emitting RF in the 2.4GHz spectrum then when will some smart-assed entrepreneur come up with the dual-function lightbulb/WiFi node?

Half the guts is already there -- the transmitter.

If every household and business had these bulbs, think of the massive 802.11 network we could build!

Each bulb could become a node in a new, better, "brighter" Internet.

Okay so I'm kidding!

Of course if that doesn't work -- why can't they just use some sheilding on these bulbs? A very thin (transparent) metal-film conductive coating (of the type they use on LCDs) should do the trick quite nicely and at minimal cost.

we need another frequency.

[beckett]

the 2.4ghz band is a mess. cordless phones, video transmitters (X.10!), 802.11, and Bluetooth all share that band of frequencies. Granted, this is what was pretty well inevitable with the FCC unrestricting the 2.4ghz band.

now there are technologies they never thought of, like interference from this light. I seriously have a problem with any of these 2.4ghz products: i'm not even guaranteed that my video transmitter will work with my phone without interfering.

i'll wait until Ultra Wide Band [gcn.com] products become available. 3.1ghz phones are just around the corner. then watch us roll into GPS territory. maybe we should just switch back to carrier pigeons (:

Too much power?

[forand]

Anyone know exactly how much power these lights are supposed to give off? If these are supposed to save power better than current technologies(e.g. florecent) they need to put out 12W. But the claim is that it interfers with 2.4GHz so how much power is going out in that band if the whole thing is only using 12W? It seems unreasonable that 12W falling off at 1/r^2(okay I assume a sphereical bulb) would have enough power to interfer with WiFi .5miles away. So does anyone know the power output(or usage) of these lights and exactly what intensity a WiFi will pick up?

FCC regulations

[panurge]

Doesn't the FCC have something to say about this? The European EMC Directive covers the emission spectrum from DC to the Big Bang frequency, and I remember well getting all the technical papers as the conventional fluorescent manufacturers faced up to the fact they were going to have to redesign their ballasts and ignitors. Even if this particular bit of spectrum is unregulated, what about harmonics? Surely they would be up there in the key shortwave radar bands, raising the noise floor?

The EMC directive: you're allowed to radiate gibberish, brain-dead stupidity, pornography etc. but NOT NOISE

Re:Uncontrolled frequencies are doomed anyway

[foniksonik]

I'd think that at some point wireless will be ubiquitous like cell bands and you won't need to broadcast your own.. isn't that what you meant by 'success story'.

Not broadcasting your own means much less interference AFAIK. This will happen soonest in tightly populated areas.. looked to Japan to be the first to have public access WiFI.

Course i have to ask how does WiFI scale to N users per square mile/km?

Re:Wind? Solar? You're kidding, right?

[Cody Hatch]

Oh good grief. Wind? Solar? These things have been "up and coming" for YEARS and they have never been successful.

The total cost per kWh (counting upfront capital costs) has been dropping for years, and has now come within a hair of hitting the cost of fossil fuels (for wind). Solar is more expensive, but advances already in the pipeline should bring it to less than nuclear within ten years.

There is indeed resistance to building wind turbines. But in case you've been asleep since the 70's, there's a little resistance to building nuclear power plants too (we haven't built a nuclear power plant since Three Mile Island). And while they kill birds, it's is (and would be, even with a massive increase in generation) a handful. Plate glass windows kill 97 million birds in the US alone (and cars kill another 50 million), whereas wind turbines in the US kill 70,000. That means it'd take a 1000-fold increase before the two are even comparable.

Also, comparing the output of a single wind turbine to a single nuclear power plant is stupid. The question is, how many kWh of production capacity does a given dollar buy you when spent on Nuclear versus Wind? And the answer is, Wind, because the turbines are dirt cheap (compared to a nuclear power plant!).

As for solar panels, they do stop producing when it's cloudy and dark (much like wind turbines stop on calm days). There are two solutions. Large storage batteries, and nuclear plants to help keep them topped up during dark, overcast, calm periods.

Your figure for solar power density isn't completly correct. That's appears to be an average figure, but solar power density depends on your latitude, and ranges from 250 to 100 betweeen the equator and the poles. That means it would only take a square 500km on a side to supply the entire Earth's energy needs if built on the equator. Of course, shipping power from the equator isn't a great idea, but the US's power needs could be met several times over by coverering half of Texas in panels. :-)

That solution isn't cheaper than nuclear (not at the moment), but solar panels have been halving in price every decade since their inception, and it looks like this will continue to around 2030 (at least). Around 2010, both wind and solar will be cheaper than nuclear, and by some estimates wind will cheaper than fossil. And don't forget, fossil fuel generation can't really get any more efficient due to the laws of thermodynamics. The only way fossil fuel generated energy prices are going is up.

Re:What nonsense.

[AlphaOne]

To be honest, I hadn't even considered Part 18! So few devices qualify for Part 18 I don't really even think about it.

These lights could very well be Part 18, although RF lighting isn't mentioned specifically in the section.

I don't know the specifics of the design of these lights, so it's really hard to say. Shooting RF energy through a glass tube to excite a gas doesn't seem like it should radiate so much energy as to wipe out wireless networks for half a mile in any direction.

Personally, I'd have reservations about sitting under such lighting all day if it did!

Part 18 devices are limited to 2.4 GHz - 2.5 GHz, which unfortunately wipes out the entire Part 15 subband. They're also authorized a much higher field strength... at less than 500 watts (which we can assume these lights will be) it's 25 microvolts per meter measured at 300 meters.

However, I still don't see these fixtures being a problem for reasons aside from the Part 15/18 argument.

Properly designed, these lights should only emit spurious emissions at very low power and at specific frequencies and harmonics within the ISM band. Spread spectrum devices should see around this interference. Perhaps the range or speed would be a little more limited, it shouldn't be a huge impact unless your base station is sitting right under one of these lights (which is possible).

Also, you must consider market pressures. If they hope to sell these devices to businesses (the largest consumer of flourescent light bulbs) they simply have to consider wireless networks. By the time these fixtures are available on the market, wireless networking will only be more common.

No enterprise is going to purchase lighting devices that wipe out their wireless infrastructure.

Re:What nonsense.

[AlphaOne]

Doh, just need to revise my previous post.

RF lighting IS specifically mentioned in Part 18 (it's early, sorry).