So I have a wireless system at home. The wireless router sits out near the front door where the main computer is. My bedroom is down the hall two doors. I use a linksys wireless router. I usually keep the door to my bedroom closed.
My question is: how do the wireless beams/rays get into the bedroom? Do they come in through the wall? Underneath the door? Do they go outside and then come back in via the window?
I ask all this because I want to make my signal go up to five bars — normally I only get three bars. Three seems to work fine, and occasionally I do get five. However, when its three, there will be times that the internet just goes down i.e. when I’m watching a youtube or listening to streaming music.
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My question is, what are you watching on YouTube in your bedroom with the door closed that frustrates you so when the stream is interrupted? (Sorry, I couldn’t help myself.)
Now to your question: First of all, the waves (radio methinks) can pass through walls, though some bounce off, which would make the signal lessened. Secondly, I suppose they could pass under a door or out a window and back, but since radio waves travel always in straight lines, it would have to involve some fancy ricochet action, and since many waves pass directly through most solid objects, the more times a wave reflects off another surface, the more it will lose intensity. I think, then, that by far the majority of the signal is coming directly through the wall. Opening the door could help, but probably not a lot. But I’m no scientist.
Your signal is definitely going straight through the walls. Your best bets to increasing your signal strength would be to get a new antenna or raise the router up a bit. Be warned, both increase the chances of family aggro.
I don’t know a ton about routers, but here are two thoughts:
1. Could you have anything like aluminum foil blocking the signal? I presume you your door doesn’t have any metal besides the hinges and knob, but maybe you have a metallicized (as opposed to Metallica) poster or insulation in the walls.
2. Does fiddling with the antennas on the router help at all? I know linksys also sells larger antennas that are designed for a longer range, although you sound pretty close to yours.
Do they come in through the wall? Underneath the door? Do they go outside and then come back in via the window?
Yes. No. Yes.
However, if for whatever reason you have a gap of at least 12.5 centimeters (the wavelength in the ISM band) beneath your door, I’ll need to change that second answer.
A little bit of physics:
Whenever light (and that’s all 802.11 is, just in a nonvisible band) passes from one medium to another, a fraction of the energy is reflected and a fraction is transmitted. The exact reflection and propagation characteristics are highly dependent on the wavelength of the light and the material. In general shorter wavelengths do a better job of propagating through dense material (think gamma rays) and longer wavelengths do a worse job. Really that’s a function of the energy content of each photon which is proportional to the frequency (inversely related to the wavelength) and the greater the energy, the harder it is to stop the photon. (That being said, in free space, lower wavelengths propagate for greater distances.) Light will also diffract (bend) around objects with diffraction being a function of the relative size of the object and the wavelength.
As to why your connection drops, that’ll be buried in the guts of your router and I can’t answer so well.
They mostly bounce off of metal and mostly go through anything you’re likely to have around (unless you’re storing degenerate matter in your house, and I don’t mean porn).
You can get weird convergence and interference points. If you move the router around, it can make a difference.
Someone was talking about reflection, but reflection is a mixed bag, and much of the reflected RF will reach the receiving antenna too. Whether this hurts or helps depends on the phase relationships between the direct and reflected signals (this is also responsible for ghosting with over the air TV broadcast signals).
Signals in phase are additive, while 180 out of phase cancels completely. In between phases vary between them, from near double the gain down to zero.
It is hard to block a high frequency signal completely though. At my old workplace, my cellphone worked fairly well inside a metal building with a metal roof. Enough signal apparently got in/out through the few small windows.
However, if for whatever reason you have a gap of at least 12.5 centimeters (the wavelength in the ISM band) beneath your door, I’ll need to change that second answer.
Do you know anyone so thin that they only have doors 13 centimeters wide? How do we know that the wavelength’s “up” and “down” conform to ours?
Unless there are a lot of wires in your wall, it won’t block the signal too much (but sometimes, that’s enough.) What we do is to have our wireless router and a signal amplifier (AirPort &Airport Express in our case.) We’ve only used the second in a few instances— mostly it’s to attach to speakers so that we can play iTunes in other rooms.
Ali, when I switched from B to G band on my home wireless network, reception rang the bell. Are you using the old system?
TBR:
I’m referring to the gap at the bottom of the door. 12.5 cm would be quite high (about 6 inches) but not impossible. If there’s a gap that big, then the ISM signal could actually fit under the door.
A similar phenomenon occurs with radio (FM/AM) signals. FM signals have a much shorter wavelength than AM. AM signals have a hard time fitting in underneath bridges and tunnels. FM signals having a shorter wavelength can fit into that gap and thus getter better coverage there (AM has to penetrate which just doesn’t happen too well).
Yes it goes through the walls. In order to improve reception, even a minor upgrade in antenna’s will help matters, over the default ones. Search for ‘antenna’ on newegg.com for a few choices.
Position can matter, remember radio waves are resonant with metal. So metal studs, or even wiring hanging in the walls, can affect the signal. A simple shift of a few feet can make a big difference.
Also, make absolutely sure the antenna’s are parallel, I have used a string and a washer as a makeshift plumbob, and once found out the router antenna was at a slight angle because the surface wasn’t true, and so was the computers, and it added up to almost 10 degrees off. A small change like that can make the difference between ‘good’ and ‘excellent’.
If you want to go science-fair like, there are numerous sites online on how to make your own antennas.
To put it shortly:
They’re radio waves.
They’re mostly going through your walls.
You can improve the reception most easily by getting the router up higher, by removing as much mass as you can between your bedroom and the router, by making it closer to the bedroom, and by a bigger antanna.
Don’t go with a repeater/amplifier except as a last resort. It’s not the ideal choice, it’s a last-ditch choice.
You’ll get no science from me, just what worked for me. I have many walls and ceilings between my wireless router and my desktop computer, and I could only get connected half the time.
I tried positioning the router, buying an antenna, and I couldn’t get it to do squat. The only think that worked was to buy a new router with MIMO support. Mine’s a Netgear, but probably 802.11g + MIMO should work. (I was able to get one refurbished on ebay for about $30)
As an aside, I wouldn’t bother with Draft-N. There aren’t any that are guaranteed to be firmware upgradable once the 802.11n standard is ratified.
Again the key feature to look for: MIMO!
“The only think” -> “The only thing”
I also meant to say there is not a single day that I cannot get onto my wireless network, whereas before it was 50/50.
You also may want to check in the router configuration (probably at http://192.168.1.1) to make sure any “range extender” options are turned on.
Because of the phase issue mentioned above, if there is a sweet spot for your antenna it should be within 6.5 incches of its current location. Another thing to do is to see if your computer is seeing someone else’s network when your router is off.
Anyway, I have a lot of fun talking to cellular RF engineers about the good old days when the 20 meter band was considered short-wave.
As others have said, it’s radio waves and radio waves can go through walls, but the denser the material that it is going through, the more difficult it is to penetrate. Like light (well, it IS light) radio waves also bend around corners and so the signal you get is a combination of direct signal from the source, reflected signals from dense objects (like pipes, conduits or solid oak doors) and refracted signals that have passed through some material to get there. Those signals all add together into one signal that the receiver amplifies. If the signal has significant out of phase reflected or refracted components, it can significantly degrade the reception, and this can actually be corrected with fairly minor adjustments of the sender or receiver.
There’s no way to tell you what to do to improve the signal without in-depth knowledge of your home construction, your furniture, your relative locations of the sender and receiver and your other electronic devices that might be contributing to interference with the signal.
The suggestions to raise the sender will probably improve the signal because homes tend to have much of their denser elements (like bookcases, desks, sofas, etc.) lower in the room, so a higher placement clears those objects from the direct signal of the router. But it doesn’t always work. Metal components of your house such as heater vents or air ducts can significantly impact reception, and sometimes those are higher in the walls so it’s not always successful to raise the sender.
In most houses the wireless signal propagates most efficiently through the sheetrock, especially if you have heavy solid wood, or metal cased doors. In general it should work fine through ceilings and floors too. But every home is different.
I’d suggest just moving it around a bit and see what works. Chances are good that you’ll find a sweet spot that solves your problem.
“Window” was what chaff was called once upon a time.
I’m not an electrical engineer (just a frustrated consumer), but I recall the rabbit ears days of television and receiving a snowy signal, stepping up to the tv, watching the picture clear, stepping back and watching it snow over.
Talk about frustration.
Now, my laptop will not hold my wireless signal. The green bars will all be lit, but after a time at home it will drop the signal. At coffee houses and bars, the wireless will hold true.
When our department head secretary is finally returned to us (she’s coding report files for a new system the department is going to roll out a year ago – the department is waiting until it actually works before doing it [score one for common sense!]) I’ll ask her.
Depending on which version of Linksys wireless router you have, you can also use 3rd-party firmware in place of the Linksys firmware and boost the power output from the router. It defaults to far less than half the legal limit.
http://www.linksysinfo.org/ can provide some information if you’re interested in following this route.
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