Howard Rheingold (hlr) Sat 23 Nov 02 15:17
Gail -- absolutely, when it comes to political decision-making, time for deliberation makes for better decisions. That's why I think some proposals for "instant electronic democracy" by enabling citizens to vote on issues in real-time are recipes for disaster. We already see that instant polling enables politicians to tailor their messages to the local audiences on a day by day basis. And as we've seen from Nigeria, not all popular demonstrations are non-violent or necessarily democratic. However -- I keep stressing this -- I think we need to see collective action in a broader and longer-term context than flash-crowds and mobs. Science, money, democratic nation-states, stock markets, the web, eBay -- these are all examples of institutions that started grow only when certain thresholds were lowered -- in terms of trust, breadth and speed of communication, affordability of communication, and other factors. Jon -- yes, that's the Benkler essay that Phred pointed out.
Dave Hughes (dave) Sat 23 Nov 02 18:38
Be careful of your terms, Howard. Electronic democracy is NOT, to be, just the act of voting. From the git go, after I set up the Rogers Bar BBS in Colorado Springs in 1980, in the place where democratic union politics had always been discussed in the Republican town, I conceived it to be a place where anyone could come on line and DISCUSS, and DEBATE the issues, and then act as they would, individually - vote, lobby, organize, whatever. For to me the American political process consisted of at least three phases - getting or distributing information, discussing and/or debating the issues, then voting, individually. What I felt had diminished greatly in America was the 'discussion/debate' (outside the narrow circle of ones acquaintences) part where (1) individuals by discussing, have to think, and by listening (reading) what everyone else has to say, make up ones own mind (2) become even more informed on the facts, as others bring in facts not disemminated by media. As one 'student' of mine (publisher of a newspaper) said "Its the New England Town Hall over an Electronic Back Fence in Colorado" For it (the BBS) obviously had several advantages over the 'traditional' political processes. (1) it was convenient to the individual to come into the discussion, just as all you do here, asynchrously, at YOUR time schedule not the schedule of announced, face to face meetings or debate (2) it is in the written, not oral, form - with operates at a higher level of cognition than verbal jousting, speaking, listening (and forgetting) (3) EVERYONE can have their say, which never can happen in any but the smallest f-t-f meetings. AND since people can read 10 times faster than other people can type, and at least 3 times faster than other people can talk, there is more 'discussion' per hour online than f-t-f. All there has to be is a light handed moderator (the most overlooked requirement in every online discussion I have ever been in - including on the Well - to keep order, keep the discussion shaped to the general purpose of the online meeting, to prevent one 'personality' from dominating everything, and even ask questions or stimulate discussion on related topics. Freeform discussions without moderation are usually failures, or do such topic drift that nothing comes out of it. (4) THROUGH the discussion it is easier for many individuals to make up their own minds. (5) the obvious disadvantages of media - one way, often slanted, very selective, and most recently dominated by those with the greatest war chest, is finessed. Bypassed. I could go on. There are many more aspects to this. The 'communications' commons, wireless or wired, can support this kind of process. Which can and will give rise to new forms of 'representative' government. But the core of what the new ubiquitous connectivity can bring, is a restoration of the 'discussion/debate' element of democracy, by which consensus, or clear divisions, or the oft observed phenonomon in online either-or debates of someone not heard from, but observing and thinking, steps in with a new idea that may 'bridge' apparent irreconcilable difference between the <exhausted> debaters, and bring things to a new level of agreement. While the number of those who won't agree (left or right) will diminish. For this nation, at least, operates on Great Consensuses. Enacted by majority vote. It all goes down to the most basic fact. Two can bargain or argue. But it takes three to politic. Each trying to get one other to agree with him. Which three now, can be spread across the world, while the process proceeds electronically. This is much different from the 'mob' action I observe. Or the tyranny of the majority, or minority. The heart of Electronic Democracy is discussion and debate between individuals. Facilitated by technology, and governed, even on a 'nobody-owns-or-controls' commons. If I run for County Commissioner of El Paso County here surrounding Colorado Springs, as a Democrat (to break the 30 year stranglehold the Republicans have had on the offices) which I have occassionaly thought of, I will employ the grass roots tools of Electronic Democracy, and the insights from the original (1980-84) Rogers Bar BBS in spades.
Howard Rheingold (hlr) Sat 23 Nov 02 21:39
I think you'll see that I was commenting on some people's ideas of instant electronic democracy, Dave. And I have no dispute with you that debate and discussion and deliberation are fundamental. I do go into detail about the role of the Internet in the public sphere in the new chapter I wrote for the 2000 MIT Press edition of the virtual community: <http://www.rheingold.com/VCnewchapter.pdf>. I think any discussion is better than sitting slack-jawed in front of the tube, but I agree with the critics of this notion that the jury is still out on whether discussions like these have had or will have a significant impact on the public sphere. But we drift. What's new on the wireless front?
Tim Pozar (pozar) Sun 24 Nov 02 06:56
Just a couple of comments. Earlier HLR wrote: > Radio waves don't physically interfere with each other -- they > pass through each other. But the radios of the 1920s were "dumb" > insofar as they lacked the ability to discriminate between signals > from nearby broadcasters on the same frequencies. It is true that radio waves don't interfere with each other. The problem happens at the antenna and the receiver. Once the electro-magnetic radio signal is collected at a point (antenna) and converted into electrical energy, destructive interference will occur if you have two signals you are trying to recover at the same frequency. New radio modulation technology, such as Ultra-Wide band and to some extent spread spectrum (such as Direct Sequence) will try to recover from interference. Protocols such as 802.11 has some "collision avoidance" built into it. Using additional error recovering schemes such as redundant transmission of the data and error checking and recovering will add to the robustness of the transmission of data to interference. Solutions for the "signal point" antenna system have been proposed and even implemented. Diversity reception is a common solution to the problem. Using two or more antennas, a receiver can determine that if one antenna can't recover the signal, try using the other. This works particularly well with "multi-path" conditions where a signal is bouncing around and may be received at the antenna as multiple signals with different time delays. Active phased-array antennas are the next step in antenna technology. Phased-array works by having two or more antennas feeding or being feed by an delay/phase network. What this means, the signal being received by the antennas or transmitting to the antennas can be delayed say anywhere from 0 to 360 degrees or some very small fractional of a second depending on the frequency. This changes the pattern of the antenna. For example, phased-array antennas have been around for a long time. For transmission, AM radio stations have been using them since the 30's to "directional-ize" there coverage area. If a station has only one tall tower for an antenna (and assuming their ground system and soil conditions are the same in all directions) they will have a pattern that looks like a nice round circle. By putting up two antennas at a particular distance away from each other and then feeding each antenna the transmitter's signal at some known phase difference and even power level, they can create patterns that look like a daisy flower. One or more "nulls" in the original circular pattern. With the new antennas the key word here is "active". Active means that you can change the phase delay of the signal on the fly so you can very quickly change the pattern of the antenna. So why is this important? Let's look at the example where you have two signals you want to recover on the same frequency. Very likely they are coming from two different directions. With an active phased-array antenna, you can discriminate between the two signals based on direction. You would change the pattern of a section of your antenna to listen to one transmission and ignore the other and at the same time, have a different section of your antenna listen to the signal you are ignoring with the first section. This is the key here... You have just increased the bandwidth of this area by twice if you can recover two signals at the same time. A big win! Recently active phased array antennas are started to be manufactured and deployed for 802.11. Vivato is just one of the companies that is spear-heading this phased-array antenna deployment. So, interference just doesn't go away with the new technologies, it just is mitigated to being a small problem. Of course this ignores the legacy systems out there that don't have these new technologies to avoid interference. This continues to be a problem and will be one for some time as changing out legacy radios and systems will take 100's of billions of USD to replace.
Howard Rheingold (hlr) Sun 24 Nov 02 07:20
Tim Pozar (pozar) Sun 24 Nov 02 08:38
But wait there's more! :-) HLR wrote: > So the regime we now know emerged -- broadcasters are licensed > to broadcast in a particular geographic area in a particular frequency > band. For the most part, licenses to chunks of spectrum are auctioned, > and the winner of the auction "owns" that piece of spectrum. Currently, broadcasters do not go through an actions for their spectrum. They originally go through a "beauty" contest if there are more than one applicant for the channel. At one point, broadcasters had to keep going through these "beauty" contests every time their license renewal came up. Beauty contests were used since the standard broadcast bands (AM/FM/TV) where seen as a "public trust". Broadcasters had to show how much time there were going to dedicated to things like news and public affairs. They were required to do "assertainments" every three months and interview various organizations and individuals to identify local issues that they should address. Broadcasters have been deregulated so they don't have to jump through these hoops any longer. This is a very large loss to the public as a major community outlet is now not available. De-regulation has also hurt community access in other ways. At one point, companies were restricted to the number of stations it could own in a market. When I started out in broadcasting in the early seventies, a company could own one station on each band (ie one FM, one AM and one TV). With the Telecommunications Act of 1996 (SEC. 202. BROADCAST OWNERSHIP) now, depending on the size of a market a company can own up to 8 radio stations in a market. This ended up creating less "diversification" of programming in market (see: http://www.futureofmusic.org/images/FMCradiostudy.pdf). Since broadcasters are in effect "own" their licenses now thanks to de-regulation, it also had the effect of increasing the price of radio station properties. The company I was working for (Brown Broadcasting) bought KDFC, a classical station in the SF Bay Area, for $15 million in 1993. KDFC and KFCF were sold by the Browns after the Telecom Act of 1996 and just a couple years later, for over $100 million dollars. Station prices all over have jumped up with the demand to own as many stations as possible by a small group of companies (ie. Clear Channel, Infinity, etc.). This has put a significant "debt load" on the companies and with stock holder pressure to increase revenue it has forced stations to look into cutting costs. (This is ignoring the problem stations ran into in over estimating their revenue and budgets after the technology bubble popped.) Cost cutting has been a prime factor to the popularity of syndicated programming. You don't have to pay for talent on each station, as you just need to pay (or barter) for a proven syndicated show like Rush or Howard. (Premier Radio who is owned by Clear Channel is raking in the bucks syndicating these and other shows). Of course with syndicated programs, you don't need to produce local programming to fill you air with. This is why other communications media solutions such as LPFM, community wireless, the Interent, etc. are so important to open to low-cost, democratic (aka, bi-directional) communication.
Dave Hughes (dave) Sun 24 Nov 02 08:53
What is new in wireless? The Leopard Changing his Spots! FCC Chairman Michael Powell, Republican appointee, who declared when he assumed the Chairmanship that he didn't know what 'the public interest' meant when applied to spectrum (or other regulated matters), pretty much took the position that the 'marketplace' - and as unregulated as possible - would solve all problems, recently did 180 degree turnaround about Spectrum regulation and management!!! While the story is long and a bit convoluted, as those of us who follow FCC closely, it appears that, behind closed doors in his office, with Dale Hatfield the outgoing Chief of Technology and *maybe* a bleeding edge ARPA wireless guru, he got a very technical education on how digital radio works and how, IF the rules were changed, how it COULD work to greatly expand the number and variety of users, while greatly minimizing interference. So in a VERY important speech at the University of Colorado just three weeks ago, Hatfield in the audience (whom he thanks) he made the most important spectrum management policy speech in memory. I have hidden its full text in the next item below. Read it carefully. Then I will amplify on what its leading to which is in the DIRECT interest ofthe growth of the 'wireless commons' and the open software movement!
Dave Hughes (dave) Sun 24 Nov 02 08:53
Dave Hughes (dave) Sun 24 Nov 02 09:20
You KNOW this is a huge switch when (1) his fellow Republican Commissioners are stunned and object to what he is doing (2) CTIA, the Cell Phone Association representing an industry which has bid BILLIONS for spectrum are objecting because he is going to GIVE AWAY (expand no-license spectrum available) more spectrum! And how is he doing it? In a VERY fast track public process, he hired, temporarily (or borrowed) Dr. Paul Kolodzy, a leading spectrum guru in ARPA (the defacto R&D arm of the Defense Department) to head up an unprecedented 'Spectrum Management Task Force' at the FCC. Formed in late June, its work done, and its report made to the full FCC last week (or two) THATS blinding speed. And Powell, mindful of the foot dragging that the full Commission can do, let the staff anounce ANOTHER unprecedented (though perfectly legal) procedure, a STAFF announced 'Public Notice' inviting, fast track, public comment on a list of provocative ideas. Normally, the staff recommends to the Commissioners the text of either an NOI (Notice of Inquiry), or an NPRM (Notice of Proposed Rule Making) and the COMMISSIONERS request the comments in public (mostly online) ways, followed by formal hearings. Even the other Commissioners objected to THIS method! For the Task Force was ONLY staff, augmented. That was fast track too. Only 200 of us were alert enough to post our comments, which the Commissioner MUST consider, during the open period. Then the comments were studied by the task force, which then made a report to the full Commission. And NOW, Powell intends to put out an NPRM - proposed new spectrum management rules - (which requires a majority vote of commissioners to even put out) very soon. And I am betting that you will be seeing NEW, more unlicensed spectrum, but even more importantly, new methods to technically deal with 'interference' AND to overcome what Tim mentioned, the Billions in Legacy 'dirty radios' by stopping the practice of grandfathering their licences in. (not to brag too much, but both the official advent of 'smart radios' and the idea of NOT giving unlimited term licences, were proposed by me and Dewayne Hendricks in our Scientific American article on spread spectrum April of '98) More in the next post, about what technical-regulatory changes are making this possible. So you can have all the gee-whiz technical advances in digital radio you want, but UNTIL (just as occured in 1984 when the first rules for spread spectrum unlicensed were promulgated) the FCC changes its rules, you have nothing, legally, you can capitalize on.
Howard Rheingold (hlr) Sun 24 Nov 02 10:02
Tim, in regard to auctions, you refer to television and radio broadcasters and beauty contests; what about the auction of licenses for "advanced wireless services" such as "third generation (3G)" broadband services by telecommunications operators? Was not the auction of certain parts of the spectrum adopted by the FCC, largely upon the advice of Nobel Laureate Professor Ronald Coase? As I understand it, beauty contests and auctions are BOTH used for different aspects of spectrum allocation. The point of all this for my book is that mobile Internet devices and the wireless technologies that support them are the locus of conflict between existing regulatory regimes and new, disruptive technologies.
Dave Hughes (dave) Sun 24 Nov 02 10:09
Now why did - or as I cynically say 'could' - Michael Powell, a lawyer 'get it' in such boundary-busting ways? (for, with the except of a handful of lawyers, such as Larry Lessig, who required a tutorial by David Reed, before he *really* understood how digital radio contributed to the wireless commons) few of them as policy makers (including Congressperns AND the legal side of the FCC house) could get beyond traditional ways of thinking about spectrum as real estate, which, if you own it, I can't. I can only recall that Powell was a commissioned officer in the Army, armored corps. Armor officers have to be damned technical and they must master and use a bewildering array of radios (including ones with spread spectrum modulation). That made him more than a lawyer in technical grasp, before an accident ended his promising military career. But why did he made such a bold policy switch? For one, the pressures on the FCC for the use of spectrum were getting enormous. SOMETHING had to be done. And the only solution, if you think of spectrum as only unsharable real estate, is to allocate it to the highest bidder. The traditional 'economics' solution. Powell himself, less than a year ago, in commenting on the exploding 802.11b Wi-Fi sales phenomon said we were heading fro a spectrum 'melt-down!' (if you view view interferece wrongly) His epiphany came after that statement. Secondly, after the bitter fights between the secret government body called IRAC which handles government uses of spectrum, and the FCC which only has jurisdiction over non-governmental use, even Congress started to get in the act - calling for more 'ultra-wide band' spectrum. The LAST thing we want is for wholly political Congress to start making spectrum policy. But in the Telecom Act of 1996 Congress decreed 'ubiquitous broadband' as an FCC Requirement. The evil and incompetant Telephone Companies, since then have shown their unwillingness AND incapability (within a sound business plan) do deliver it EITHER 'the last mile' OR to rural Americans. Wireless had begun to rise as the ONLY solution, first with weak-kneed 3G (a very costly incremental step toward cell broadband). But then all those Pringle Cans in Seattle, followed by big non-telco companies - Cisco, Motorola bringing out unlicensed wireless devices with ranges (line of sight) out to 20,30,50 miles, all got the presses attention, some FEW of whose reporters get the technical reason why high speed non-interfering wireless can work. And even the myth that all wireless must be insecure is fading, as wireless encryptian and authentication arts have advanced. So there were lots of reasons the FCC, rather than just keep rearraning the chairs on the deck of the Titanic by making tiny changes in the radio-certifaction rules, had to do something. MEANWHILE tremendous advances in radio and antenna technolgies, integrating them into Internet protocols, and the REAL economics of wireless, which is the falling costs of wireless devices, not the price of spectrum, offered solutions 'in the public interest.' i.e. grass roots users, not just corporate, communications-for-a-cost-per-minute (telco) solutions. And not incidentally, DOD and ARPA, whose job it has been for the past 40 years since the love of my life Hedy Lamarr invented spread spectrum and gave it to the Navy in an act of patriotism, has been to push the technical envelope at government national security expense, to make the best, fastest, most secure, forget the need for license, radio and data radio communications. So ARPA is probably 5 years ahead of industry in these matters. And those advances have been handed to the FCC via Powell, so they could be integrated into commercial radio systems, with corresponding permissive rules. All those combined, to me (this is just my personal theory) accounts for the Republican leopard changing his spectrum spots in YOUR interest. (I should not put down fellow Republican Commissioner Copps completely. For HE is very concerned about RURAL connectivity. And since I have fought for years to get the FCC to differentiate the spectrum rules for use (power, especially) for Urban versus Rural, maybe I can help him see that the new wireless paradigm, UNLICENSED, can go a very long way to solve the rural broadband connectivity problem. Hell, I just took delivery on a pair of costly Canadian radios that, under *current* rules can deliver 45mbps as far as, reliably, 30km, have been clocked at over 70 miles, at a lower rate. But pure line of sight required (and the lower the frequency the less line of sight, which plagues Wi-Fi radios, is required).)
a man, a plan, and a parking ticket (clm) Sun 24 Nov 02 11:16
Wow. Thanks. This is very exciting stuff. Here's a CNN article on a commercial product that appears to be very much in line with what you folks are talking about: http://www.cnn.com/2002/TECH/ptech/11/23/new.spectrum.ap/index.html Are there other efforts like this that are underway? What about the big manufacturers of hi-tech radio products (mostly cell phones, I guess)? Are they enthusiastic about software defined radio or do they see this as too disruptive? And what's the status of grass-roots experimentation with this technology? Are inexpensive software defined radio transceivers available? I would think the amateur radio community, for example, would be having a field day(!) with this stuff.
Dave Hughes (dave) Sun 24 Nov 02 11:26
Howard, 'Auctioning' of spectrum was ONLY needed if you assumed fixed, non sharable, spectrum. No matter what Nobel prize winner Economist proclaimed it as a solution. What is changed, which you call 'disruptive' technologies, I call 'shared spectrum' technologies. A good 9-10 years ago, Dr. Paul Baran, testified in front of the FCC Commissioners, that the spectrum allocated to television, (jealously guarded as if it is 'their' property) was a vast empty of traffic the very vast majority of time, could have digital signals passing through it, that would have to be 10,000 times stronger in power, before any interference would be noticed in analog tv reception. Paul (who invented Packet Switching) just about gave up on the FCC ever doing anything better. But I have learned he is *delighted* at the Powell pronouncements. I say again. Never solve by regulation or law, that which can be enabled by technology.
Howard Rheingold (hlr) Sun 24 Nov 02 11:26
Intel's CTO claims that future chips will incorporate SDR technology: <http://www.siliconstrategies.com/story/OEG20020228S0035>
Howard Rheingold (hlr) Sun 24 Nov 02 11:27
If spectrum is deregulated in an "Open Spectrum" fashion, won't the devices be regulated in order to play nice?
Dave Hughes (dave) Sun 24 Nov 02 11:39
Craig, (clm) although the telephone companies are desperately trying to push the cell phone envelope, the Bell Heads are never going to catch up with the digital wireless + IP radio crowd. And the telcos are in such financial trouble, there are plenty of predictions many of not most of them will go bancruptcy under before they can reinvent themselves - which takes HUGE investments AND the write off of their legacy circuit switched systems. Even 3G, which to me is just an incremental advance in cell-phone based data/voice networks is going to require damned near double the number of cell phone towers NOW in place, in order to get close enough to 3G consumers to give them the data speeds they want. Whose going to pay for it? If you find any 'low cost, software defined radios' for sale, they are probably illegal, for the FCC has yet to announce (last time I checked) ANY rules for the manufacture of such type radios. See? Its the chicken and egg. You can't make, sell, or use radios unless they are certified by the FCC under rules governing its design. And no company is going to spend the $$$ to design a radio that they are not 100% sure will be approved. And if there are no rules for the design of software defined radios, then they won't even try to make them, except at the tinkerer level.
Howard Rheingold (hlr) Sun 24 Nov 02 11:47
There's GNUradio: http://www.gnu.org/software/gnuradio
a man, a plan, and a parking ticket (clm) Sun 24 Nov 02 12:07
Thanks, Dave. Isn't there still some radiated power threshold below which the restrictions don't apply? If a manufacturer wanted to get a leg up on the competition, couldn't they initially introduce a very low power product (perhaps with programmable output power) that would allow them to start selling to early adopters? And isn't the risk of designing a transceiver before the new rules are established greatly mitigated by the software defined nature of such a product? So before the rules are finalized, software limits the device's output power to whatever low levels are currently legal. Once new regulations were in place, software upgrades could be released that would enable transmissions at higher power. Does that seem feasible? > 65 Powell's speech mentions "interference temperature" which, if I'm understanding correctly, might take the place of power and frequency when it comes to regulation. > 67 Thanks. Following that link right now.
Dave Hughes (dave) Sun 24 Nov 02 12:29
You are absolutely right, (65) Howard. The design, within very carefully designed limits, will have to be approved (certified) by the FCC. So they play nice. I don't have a problem with that. While I have a big problem with spectrum-use regulations. IF a set of rules are promulgated AND PERPETUALLY UPDATED (every few years during this time of great innovation> for more advanced, play nice, radios, then there can be true COMPETITION between manufacturers and start ups! There is NOT now when spectrum is controlled by one company, and its legacy radios. There is a splendid example of this. Its the UNII bands (Unlicensed National Information Infrastructure) which Apple proposed a long time ago, and which was duked out between them and AT&T at the FCC. If you go to http://img.cmpnet.com/nc/1324/graphics/1324f2b.gif you can see these unlicensed bands in the 5.25 thru the 5.825 Ghz frequency ranges. Even though there were, and are, a set of bands which MUST be spread spectrum modulation, radio designers can made radios in those UNII bands that do NOT use spread spectrum - either direct sequence or frequency hopping, which 100% of 2.4ghz radios must use. Now it took years before the first UNII radios way up in those frequencies (which requires even MORE rigerous line of sight, AND which can't penetrate walls or trees/leaves worth a damn). And everybody used differnet methods - within the UNII design rules. Now, today, there are many manufacturers of UNII radios - Western Multiplex, Interwave, RF Datacom, Cisco Aironet, Proxim, Tsumani, Resonext, Zcom, and the latest entry into the marketplace of Redline (Canadian) and Motorola's Canopy. What is different is the different modulation they can use. Motorola was always a leader in FM radio, so their UNII band Canopies, which are right now hot in the market (for they also do interesting things with antennas) build on that technological base. And have brought the price down. The latest is Redline AN-50, which has brought the price down from about $20,000 each end (which I recall the Western Multiplex's were for a rated 100mbps (a 'real' 60-70mbps), to $6-$7,000 each end for a 45mbps DS3 speed at 50 miles!! The UNII radios are mostly used for backhaul, but hey, you wanna go to a small town from a big town 30 miles away and serve ALL Wi-Fi customers? Thats a bargain. Care to price out a Qwest DS3 line for 30 miles? (I'd be astonished if its less than $15,000 a MONTH) What's the point? With all the attention on the rules for design of radios so they play nice, REAL competition can begin, where the best radio, will win, not the highest bidder for spectrum in a lucrative market. Ignoring the rural, small town, remote ranch, market.
Tim Pozar (pozar) Sun 24 Nov 02 14:16
Re: http://img.cmpnet.com/nc/1324/graphics/1324f2b.gif Unfortunately it is wrong or at best confused. Part 15.247 actually gives different power limits depending on if the system is "point to point" or "point to multi-point". At 2.4GHz, "point to multi-point" is limited to 1 watt (30 dBm) transmitter output and 6 dBi of antenna gain or 4 watts (36 dBm) EIRP. If you reduce the transmitter output below 1 watt, you can increase the gain of the antenna the same amount. For instance, if you reduce the transmitter output by half (-3dB) to 1/2 watt (27 dBm) you can increase the antenna gain to 9 dBi. BTW you will always be limited to 36 dBm EIRP with this rule. 9 dBi + 27 dBm = 36 dBm EIRP. For "point to point" it is a little more complicated. You are still limited to 1 watt of transmitter power, but for every dB of antenna gain over 6 dBi, you only need to reduce the power 1/3 of a dB. So if I had a high gain antenna such as a 24 dBi dish that I want to use to get my signal across town, I only need to reduce my power to 1/4 of a watt. Or... 24 dBi - 6 dBi = 18 dB 18 dB / 3 = 6 30 dBm - 6 = 24 dBm or .25 watts. With this arrangement I would be running 48 dBm EIRP (64 watts) with 24 dBi (antenna gain) + 24 dBm (transmitter power). If I had an antenna that had 48 dBi of gain I could run 64 dBm EIRP or 2,511 watts. There isn't a limit to EIRP. Part 15.247 also covers operations in 5 GHz, but power has yet another defined limit here. "Point to Multipoint" is as defined above for 2.4 GHz but "point to point" does not require the transmitter be "turned down" as the antenna gain goes up. With an antenna with 48 dBi of gain I can run 78 dBm (63,095 watts) EIRP. Cooking! Again, no limit for EIRP. As you can guess, if you engineer your paths right, you can get some pretty good distances with these devices.
Howard Rheingold (hlr) Sun 24 Nov 02 14:22
Of course, the wireless conundrum is one chapter in Smart Mobs. I'm backing up to a higher altitude to look at the big picture -- what emergent social phenomena might we expect when computationally powerful, inexpensive, mobile, wireless devices proliferate and mesh via peer to peer methodologies, perhaps using reputation systems -- in an environment pervaded by numerous radio-linked sensors and chips?
Chris (cooljazz) Sun 24 Nov 02 15:27
<#45 > ".....that people tend to overestimate risk when making decisions. ..." Howard yes, though I believe the Nobel was awarded because rather than note the problem - the investigators studied why the overestimation might happen (hence the involvement of the Economist-psychologists). Though I need to segue to discussion of the bigger question you pose "....What emergent social phenomena...chips?"
Jon Lebkowsky (jonl) Sun 24 Nov 02 15:43
At a recent talk Bruce Sterling used superballs with embedded modem-squawkers to illustrate ubiquitous computing - bounce 'em and they squeal like a modem handshake. The idea was that, in The Future, you have smart devices that communicate, and they're bouncing around everywhere in your environment. Hope they're quieter, though. So there's person to person, person to system, system to system... the future's a complex web of signals.
Dave Hughes (dave) Sun 24 Nov 02 15:54
'...system to system.' Bluetooth is just the leading edge of this industry.
Howard Rheingold (hlr) Sun 24 Nov 02 16:27
My chapter on "The Era of Sentient Things" looks at two opposite-facing aspects of ubiquitous computing as it will emerge over the next ten years: information-computation-communication embedded in objects, and information associated with places. There is an overlap between these two sides of chips in everything, located everywhere, communicating with each other and with mobile devices: bluetooth or other wireless "beacons" that broadcast and receive information associated with a geographic location. But the non-overlapping aspects are important, too. First, the matter of chips in things. The notion, certainly not a new one -- I talk about my encounters with Mark Weiser, and his ubicomp research at PARC in 1991 -- is that the cost of Radio Frequency ID tags will drop low enough (the "penny chips") that they will begin to replace bar codes. Within the last week, Gillette announced that they are buying 500 million RFID chips, so the penny chip is hardly a far-future projection. The importance of chips associated with objects is that every thing has a story -- but not everyone knows every thing's story. Labels, for example, are highly political objects. A story that happened long after I finished the book. In fact, it was a couple weeks ago. I was visiting Marc Smith, who was the main character in the chapter about the sociology of cooperation. He had connected a $150 bar-code scanner to a handheld computer with a wireless Internet connection and added software that connected the information returned from the Universal Product Code database to Google. What the heck? He urged me to try it for myself. I took the thing in hand and scanned the first two objects I encountered in his kitchen -- a package of prunes and a carton of Kellogg's Cracklin Oat Bran. The distributor of the prunes, the UPC informed me, via text on the pocket PC screen, is something called "Sun-Diamond Growers." I Googled the name. The second link that came up was "US versus Sun-Diamond," a Supreme Court document authored by Anthony Scalia, about Sun-Diamond's lobbying practices. The first link, from Corpwatch, about "bromide barans subvert democratic process," claimed" Sun-Diamond's $700 million in revenues funds their lobbying against local, state, national, or international controls on methyl bromide, according to Corpwatch. Try it yourself: Google "Kellogg's Cracklin Oat Bran" and the first link will be about a recall"Kellogg USA Issues Allergy Alert on Undeclared Eggs, Milk, Soybeans, or Almonds in Kellogg's® Cracklin' Oat Bran." Labels are closed systems, and what they don't reveal is often more important than what they do reveal. When RFIDs replace barcodes, that information becomes readable and writeable as the product or object moves through the world: technically, in the near future, you would be able to point your handheld gizmo at a slab of meat in a supermarket and ask it if it sat in the sun for three hours yesterday, or point at a book and ask what the Times has to say about it, and what the people in the Well's book conference say about it. If we carry or wear powerful computers with wireless communications, we'll be able to tap into the networks of thing-to-thing communications as we move through the world -- and things will sense things about us when we draw near them, whether we know it or not. What becomes possible? Opportunities? Dangers? What is likely. Who will move to control, and why, and how? The current open system known as Usenet, for example, makes it easy enough for any individual or group to publish information about any particular thing: post your opinion of Kellogg's Cracklin Oat Bran, and it can be Googled a few days later. Similarly, it is easy enough to use Usenet to associate information with places: Just start a newsgroup: "alt.latitudeX.longitudeY" and postings become findable by anyone with a Net connection a few days later. "Information in places" has its own set of possibilities, worth discussing on their own.
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