What part of Part 15 didn’t you read?

10/25/2011 1:11 PM EDT

Often a wire is the best, cheapest, most secure, most reliable connection between points A and B--let's never forget that in the rush to "wireless everything".

10/26/2011 1:38 AM EDT

Problems are already happening. For example, I know of a functioning ISM 2.4GHz system with small external antennas working just fine here in the US but gets clobbered by QRM in South Korea. The only way to make it work well is to strip away the external receiver antenna and reduce the overall gain of signal levels into the receiver from anything else but the closest paired transmitter. To maintain high quality signals, and good distance, the transmitter runs its maximum output with an external antenna. This only adds to the overall QRM.

I have no idea of what the ISM 2.4GHz spectrum looks/sounds like in Korea, but it is crowded.

10/26/2011 2:19 PM EDT

So we are talking about something happening that has been warned about for years.
Lets learn from another area where warnings were ignored - finance. Finance did not 'oil the wheels'; it created friction, by taking a slice of every transaction; it disrupted stable arrangements in order to get slice of the recovery processes, and it never actually created a solitary cent of net wealth. It won't continue, the inequalities are too great and in the internet age, too obvious, but is anyone going to take avoiding action?

A clean, organised, well-policed RF spectrum could deliver new products and services for centuries, but we will pollute it faster and faster with poorer and poorer-quality products until it hits a ceiling of impracticality, and the opportunities and value to industry will disappear like a seam of ore in a worked-out mine.

And we're just gonna sit here and talk about it? Ideas, guys, ideas please!

10/26/2011 4:35 PM EDT

That's why we have cognitive radio. You first see whether a given band is available, and then you start using it. Oh, just like 802.11 has been doing for years already.

For short range wireless, like 6lowpan devices are expected to be, this works reasonably well. Because typically, it is the strongest signals, in this type of network, that matter most. This does not work well in mands like the GPS band, or even TV bands, obviously, because there very weak signals are the ones you want.

Yes, there are those ill-behaved appliances like microwave ovens. Nothing new there.

10/26/2011 8:55 PM EDT

Now I am inclined to see how much disruption a leaky microwave oven can cause in some commercial areas! Of course, it certainly is correct to assert that wired connections are both more reliable and more secure, and now, we realize, they are more likely to be free of interference. The harsh reality is that for a huge realm of connections, wireless is a stupid choice, adding cost, complexity and additional power consumption , and providing only a marginal, at best, benefit. So here is the question again, that was asked a few years back, which is: "what happens when all of the channels are occupied?" How will the new toy work when all of the channel frequencies and all of the time-slots are already in use?
Of course, all of this is ignoring the question of what benefit is delivered by a toaster with an IP address. That is a separate issue altogether.

10/26/2011 9:24 PM EDT

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10/28/2011 12:51 AM EDT

I had a problem with interference from a cordless phone operating on 2.4Ghz. The Wifi router was set to auto channel, as there were no competing Wifis around that always meant the first channel. I set the Wifi router onto a fixed channel at the end of the channel list. Problem solved.

10/31/2011 7:27 AM EDT

Good article

11/2/2011 4:39 AM EDT

I was thinking about this the other day. We used to use wireless communication to distribute signal broadly, as in a commercial radio station. Everyone seems to want to access this in a wired connection now, the internet.
Meanwhile, for simple point to point short range communication, we used to use a wired connection, as in from your CD player to your preamp. Everyone seems to want to use a wireless connection for this now, like from your keyboard to your computer. Interesting, ain't it?

11/2/2011 11:38 AM EDT

My AT&T U-Verse gateway has ethernet jacks and wi-fi. I figured there was zero benefit to using wi-fi with my desktop PC three feet away, so I plugged in with a 2m Cat5 cable. Wrong! A thunderstorm blew in. I shut my PC down as a precaution, even turning the surge arrestor outlet strip off. A utility pole around the corner took a hit and my motherboard was toast. I bought a cheap USB 802.11g radio. As the EMC gurus say, only ground your system at one point.

11/9/2011 4:29 PM EST

"It’s not impossible to make these things work, it’s just really hard..." Often it's not "hard" but "more expensive," meaning "more than someone wants to pay." I've peeked inside lots of RF boxes and asked myself, "How did this EVER get certified?"

An interesting side effect of this whole Part 15 thing, mentioned in the original article but usually NOT comprehended by the general public, is the "must NOT interfere with a licensed user" aspect. Someone who purchases a consumer Part 15 device that interferes with a licensed user of the same spectrum is required BY LAW to STOP the interference. This is often difficult to explain to a non-technically-savvy individual :-) It is really hard for them to understand that they can't use something they bought. It is difficult to get across the notion that the law protects the licensed user and not them with their (probably cheap) consumer-grade item...

2/20/2012 5:11 AM EST

Mmm.. I think this is not a real problem, because devices under 6LowPAN use a very low duty cycle, so they are using the channel only a few period, and do not collapse other devices. Wi-fi uses extensively the medium, but not the WSN.

2/20/2012 3:43 PM EST

Clearly we need the white space spectrum for more ISM.