I note that the OPERA report (Open PLC European Research Alliance, Document OP_WP1_D5_v0.9.doc) indicated a lot less than 200 Mbps of information capacity on typical European systems.A better guess seems to be 20Mbps on a good day. Thus, with your estimations, more like 50 kbps per home with conventional BPL/PLC techniques (below 80 MHz) seems likely. All the more reason to move it to microwave-over-powerline. n6gn
Don't confuse the user connection with the 'backhaul' which is the over-power-line part. However, also don't confuse 200 Mbps on a lab bench with a lot less than that over a single hop on real lines having excess noise, attenuation. The 200 Mbps hardware may only need 20 MHz of spectrum in the 4-80 MHz region to support that raw rate but after a few links are chained together throughput will likely be a LOT lower than that. Now aggregate 1000 homes onto that backhaul and you may scarcely have enough performance. Fortunately, the smart-meter requirements for average data rate and latency are probably very small so it might all work fine - except for the ingress/egress radiation problems from the line which could be a show stopper. Too bad they don't move it all up to microwave-over-power-line and avoid the interference problem at the same time they get 10X or more capacity improvement. disclaimer: I resemble the above remark. n6gn
Consider 77 satellites, each catching [100 watts] of solar power that you perfectly turn into useful, information carrying RF, and then perfectly overlay so that the entire surface of the earth is covered. That sets available flux at ground level, You can't use more gain and not lose coverage area (location independent access). Now add users with omni-directional antennas. User antennas must not only be small but generally omni-directional - they have to see all the sky and can't be high gain beams constantly pointed (too big, too expensive). The associated antenna aperture determines captured power. Because of system noise temperature (antenna sees terra firma no matter what NF the equipment has, S/N ratio is determined, thus due Shannon capacity of link is set. Guess what, it's not much to write home about if you plug in reasonable numbers. A few users on each satellite can get a little bit but all users can't use it all (or much) of the time. And we haven't even talked about backhaul, real-world efficiences etc. This problem is akin to the problem of getting 3G or 4G mobile networks to work everywhere. They don't and won't unless the paths are shortened greatly and the density of points-of-presence (cell sites) is greatly increased. n6gn
inflame writes "A new paper published in Nature has said that the proton may be smaller than we previously thought. The article states 'The difference is so infinitesimal that it might defy belief that anyone, even physicists, would care. But the new measurements could mean that there is a gap in existing theories of quantum mechanics. "It's a very serious discrepancy," says Ingo Sick, a physicist at the University of Basel in Switzerland, who has tried to reconcile the finding with four decades of previous measurements. "There is really something seriously wrong someplace."' Would this indicate new physics if proven?"
eldavojohn writes "You may recall the hapless engineer who left a fairly sensitive iPhone at a bar recently. Well, in a PR stunt, Lufthansa has invited him to visit Germany on their dime after citing his latest Facebook status, 'I underestimated how good German beer is' as well as his obvious passion for German beer and culture. It's not clear if Gray Powell has decided to 'pick up where he last left off' (as the letter puts it). I know what my decision would be."
http://www.sonic.net/~n6gn/ocar/ocar.html This is essentially what one does with after market cellphone amplifiers, but the link offers more detail of the theory and what it takes to operate them properly. These amplifiers are bi-directional, both uplink and downlink are supported but in opposite directions. Use two isolated antennas and make the one pointed at the cell site (particularly) as directional as possible. I suggest a $50/$75 3' parabolic 'grid' reflector for PCS/850 MHz respectively. The ones offered for WiFi (2.4 GHz) actually work very well on PCS but not at 850 MHz and offer ~24 dBi gain. If you are really cheap, build corner reflectors http://www.sonic.net/~n6gn/corner.pdf.
We hear with our brains as much as with our ears. Simply buying hardware to compensate for the roll-off is NOT the solution. Hearing is tremendously adaptive and interactive. When you buy HAs from a reputable source you are actually buying a lot of visits for measurement/modification to allow you to adapt to the augmentation as well as possible. This is unique to each individual. This easily adds up to MANY (10-20/year) office visits over the life of the device(s). I too used to think that simply measuring the roll-off and applying compensation was a solution. It emphatically is NOT. Before you all attribute the cost of the hardware to greed, take a look at the service and also look around and find evidence of overly-fat audiologists. I don't find them around where I live... n6gn
Warm up a cup of coffee in your microwave oven and drink it while you look over these measurements I made at my house: http://www.sonic.net/~n6gn/EVDOforums/radiation.pdf n6gn
An anonymous reader writes "A Queensland man will have to pay Nintendo $1.5 million in damages after illegally copying and uploading one of its recent games to the internet ahead of its release, the gaming giant says. Nintendo said the loss was caused when James Burt made New Super Mario Bros Wii available for illegal download a week ahead of its official Australian release in November of last year. Nintendo applied for and was granted a search order by the Federal Court, forcing Burt to disclose the whereabouts of all his computers, disks and electronic storage devices in November. He was also ordered to allow access, including passwords, to his social networking sites, email accounts and websites."
Most modern phones and PDAs run no more than 400 mW maximum (+26 dBm). However, that is not a typical level. Most systems utilize power control as part of the protocol. CDMA, for example, updates the channel power ~800 times per second. It is a goal of the system to use no more power from the handset than necessary to achieve parity among users sharing a system. Average transmit power may be sub-microwatt (http://www.sonic.net/~n6gn/EVDOforum/radiation.pdf It's true some may spend more time with their phone at their ear than warming food but peak exposure from 'good' microwave ovens, never mind leaky ones, may dwarf that of communication's RF. n6gn
Kyle Hamilton writes "The Apache Software Foundation and the Apache HTTP Server Project are pleased to announce the release of version 1.3.42 of the Apache HTTP Server ('Apache'). This release is intended as the final release of version 1.3 of the Apache HTTP Server, which has reached end of life status There will be no more full releases of Apache HTTP Server 1.3. However, critical security updates may be made available."
I'll supply the power over a single conductive cable 1 km long if you'll supply the robot to climb it. We can share the prize. I'm ready to demonstrate. To see how I do it see http://www.corridor.biz/FullArticle.pdf n6gn
Glenn Elmore writes "A new type of electromagnetic transmission line system with information capacity second only to optical fiber, called "E-Line", has been invented. Categorically different from the approach used by existing "Smart Grid" power line technologies, it enables an overhead power line on the worldwide power grid to transport information at multi-Gbps while at the same time it delivers power to end users. Although greatly suppressed, the surface-wave propagation mode that allows this has always existed in common coaxial cable but since the invention of coaxial cable in the 1890's by Tesla and others, hasn't been recognized. (Disclaimer: I invented it)"
Link to Original Source
Link to Original Source
Another way to view this fundamental wrong-tool-for-the-job issue is in considering the information rate you need to support for a phone call, by comparing a 2-way audio channel at ~10 kbps with a 3G data channel at whatever you call 3G but lots more than 10 kbps. This "3G overhead" in both up and downlink directions requires a better radio path than for the same audio call, everything else equal. Less energy needs to be transmitted for the audio call. While protocols can play games with this fundamental fact (as does EVDO by forking over the *entire* base station carrier to one user at a time and time-slicing (oversubscribing)) the fundamental service, there's no free lunch. Your limited battery and antenna size limit the range at which you can communicate with a given hot-spot/cell-site and requires that there be higher site density to serve a given user base. This means that a WiMax solution will fundamentally be more expensive than an old voice-only solution. In the end (whenever it all catches up with the user) this will be more expensive. Simultaneous higher data rates to all users (3G) takes more capacity/coverage than 2G. You can borrow coverage from capacity and vice-versa but someone has to pay and in the WiMax case payment will probably be initially in the form of reduced coverage area and more expensive plans. If it hasn't already hit the wall as in the case of 3G (notice how US coverage is only a few percent of the geography compared to 2G?) it will definitely do so with 4G. WiMax can throttle down to something around 1 Mbps but not a lot lower. There's 100:1 (20 dB) difference in energy delivery requirements between these two rates. This fundamental system cost is going to keep it from being an effective replacement for audio-only communications. n6gn
I'll say! Sheesh, If your head weighs the same as a bowling ball, that means the ENTIRE output of a cell site has to be *coupled* to your head. This is easily 100,000 times more power than one would receive 50' away from a typical cell installation. It would be 100 or more times the entire output of most handsets and probably at least 10,000 times the maximum that would likely be coupled into tissue. I don't understand how this test is supposed to be relevant to cellphone use by anyone, anywhere. n6gn