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if you were unaware there's even wifi-blocking wallpaper marketed by someone like DuPont UK defence contractor BAE Systems has developed a stealth wallpaper to beat electronic eavesdropping on company Wi-Fi networks. The company has produced panels using the technology to produce a screen that will prevent outsiders from listening in on companies' Wi-Fi traffic but let other radio and mobile phone traffic get through. The FSS (Frequency Selective Surface) panels are made in the same way as printed circuit boards - layers of copper on Kapton polymer - and used on stealth bombers and fighter jets. They come in two varieties: passive, which is effectively permanent, and active, where various areas can be switched on and off to enlarge or limit the area of the network. The panels are 50 to100 microns thick and can be applied to most surfaces including glass. A company spokesman claimed that they also helped reduce "noise" in buildings where a number of companies operate their own separate LANs. BAE Systems developed the new material with £145,000 of funding from the Radiocommunications Agency, which is now part of Ofcom. BAE says the material is cheap and it will be developing it commercially through BAE's corporate venture subsidiary. |
Beware that "Wireless N" is an absolute zoo. There are lots of variations possible. Which one do you have? Many require cooperating hardware at both ends of the link. Multiple antennas for spatial diversity are a minimum. But there are many, many other variations.
IEEE 802.11n-2009 - Wikipedia, the free encyclopedia |
Originally Posted by mixture
(Post 6436139)
More like BAE Systems.... to quote a press release (from 2004) :
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Think the issue with wireless is generally more about multipath 'self' interference than brute signal strength. I don't know the 'logic' windows applies to latching on to a signal but it seems impenetrable to, erm, logic. Are there any big chunks of metal in the LOS (eg hot water tank or an upmarket range cooker) ?
While you can't beat a straight forward cable connection that isn't always possible. I did buy powerlink connectors (din't know about the sw interference) but a new router happened along (with 3 aerials) and that solved it, so haven't used the mains. In teh early days I spent many (many many) hours faffing about with dlink stuff and wds with no consistent results (laptop would 'pick' the wrong signal) and only stopped when the wife decided I should do something more productive with my life. So I think I would make sure neighbourly interference wasn't a problem (netstumbler or something), try channel extremes, make sure the network card settings are right and then if necessary spend £50 on something with lots of aerials ! |
Originally Posted by Mr Optimistic
(Post 6436371)
So I think I would make sure neighbourly interference wasn't a problem (netstumbler or something)
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Those powerline devices should be banned! I suspect that if the RSGB gets OFCOM to do its job, they will be. As said, they will only work if both ends are on the same phase, and then only over a limited distance. Meanwhile, they are transmitting on frequencies for which they are not authorised, and causing interference to the services that are authorised for those frequencies.
I've developed a simple rule of thumb that says a typical 802.11g wireless router has a range of 50 feet, three normal internal walls, two brick walls, or any permutation thereof. I think a Cat5 cable heading towards your house to as close as it can get, with a wireless access point on the end of it, is the way to go. If the Cat 5 will reach all the way, so much the better. With wireless, it is (as said above) important to "sniff" the spectrum and pick a channel away from others in the neighbourhood. Then see if it works - if not, there may be a cordless phone around, in which case try another channel. |
Powerline works just fine for me and I don't find it interferes with anything else. I only use it to hook in the DL360 which lives in the garage roof-space, the house is all wireless. I'd suggest wall thickness and environmental concerns are likely to be huge variables in all instances. Fortunately my house is fairly new so the wall are made of cheese.
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Powerline works just fine for me and I don't find it interferes with anything else. |
From one brand I read this:
HomePlug has expended substantial efforts to ensure that products designed to the HomePlug specification can meet these requirements. To meet the radiation limits imposed by FCC part 15 rules, the specification limits the maximum signal level that can be injected on to the power line. Tests conducted by FCC certified labs in various regions of United States show that the maximum signal levels incorporated in the specifications result in emissions that are below the part 15 limits. HomePlug also limits its power spectral density around the amateur-radio bands by inserting 30-dB notches for the HAM bands in 4.5- to 21-MHz HomePlug frequency range. Due to this notching of HAM bands, only 76 OFDM carriers are usable in HomePlug products operating in United States. Joint testing conducted by HomePlug and ARRL showed that, in general, with a moderate separation of the antenna from the structure containing the HomePlug signal, interference was barely perceptible. HomePlug is also compatible with other low speed powerline technologies like CEBus, X10 and LonsWorks as they operate in different frequencies. There seems to be some vehement protest about these units but given the thousands in use is intereference a real or theoretically possibole problem? |
4.5- to 21-MHz How considerate! Especially if you want to operate on 80mtrs or Top Band. |
30db isn't much when you are in the vicinty, sounds like an admission of guilt. SW receiver specs look for 'skirt' rejections of 60db (if I remember) and noise signals at 1 microvolt/metre. Had a big argument with Phillips when the first colour tvs came out as they wiped everything below 14MHz.
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So, would a street with a powerline-networked house(s) cause more problems with short wave radio enthusiasts, or would a street full of WiFi networks be worserer?
Found the following text to see if I really am a bad person with my 85Mbps PLT. "The 200Mbit devices are only a problem on the shortwave bands, so unless you listen to shortwave radio broadcasts or CB then you won't notice any problems. However, if you ever decide to upgrade to the new Gigabit versions, or one of your neighbours gets them fitted, then you might notice problems with FM and DAB." Only asking! Let's all play nicely, now. |
Blimey, DAB would be an issue :)
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Haven't had time to do much today . . . thought being old was going to mean cruising all the time.
Found out it is a Netgear unit. Downloaded and installed inSSIDer, thinking I should get to grips with it before wife has a go at it. However, it told me I needed Auto Configure on, and any interruption to my system right now would cause chaos as I near my departure date, so chickened out. I can't mess with my pal's system at all. No way I can run anything out of a newish conservatory, 'twould be like fitting a snazzy spotlight to a spaceship - it would surely leak, and the white plastic swarf would give me away. It's going to take time to really digest the posts (thanks for them by the way.) so it may be covered, but very simply, can I add something to the laptop and hang it out of the window? (the something, not the laptop. :hmm:) Then, is it simply a case of turning off the wi-fi switch on the front of the HP, and setting up the something on a USB input? Both our laptops are on Vista, bit of a nuisance, but they were both incredibly cheap. |
Try a USB WiFi dongle. You can then use a USB extender cable to place the dongle in a window (or try other places around the room). They are priced from $15 to LOTS.
The extender cable has a male connector on one end, female on the other. They are not extremely common. |
is intereference a real or theoretically possibole problem? See the link to the BBC white paper I've already posted on this thread for one of many possible examples. I hope RSGB win their lawsuit and the things get properly regulated. |
Loose,
1. Walton on the Naze has never, ever, ever had a looong summer. Neither has Frinton. 2. I would vote for the Homeplug. Mine works very well and does not disturb any broadcasts. None. |
2. I would vote for the Homeplug. Mine works very well and does not disturb any broadcasts. None. |
Summer of '59 was spiffing. Swimming in the backwaters was like a heated pool.
Noticed on Giggle Earth, I can get a triangle from one of his shed roofs back to the flat's rear window. That seems to spell out a signal booster. Though I'm not sure how long it would survive there. In haste. |
You have a shortwave receiver then and have checked all the broadcast bands between 2.3Mhz and 26.1Mhz then. For most people, the homeplug would seem to be a good solution. Talking about this to friends locally I've discovered that they use it between their main property and and outhouse used as a study, and it works well and has not caused any interference with various hifis, wifis, satellite and terrestrial TV, or normal FM (95-105 Mhz) and AM (MW) broadcasts. |
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