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-   -   Calling Wi Fi Guru's - Advice? (http://cellar.org/showthread.php?t=16330)

Elspode 01-06-2008 01:45 AM

Calling Wi Fi Guru's - Advice?
 
I've got a standard issue Linksys wireless router (G). I've located it in my basement, under the first floor, at the end of house where our office is located on the second floor. Reception and performance is just fine at this end of the house, but falls off pretty drastically at the other end. I've added the high gain rabbit ears on a remote stand to the rig.

What I think I need is a repeater, if my limited research is correct. Mounted on the second floor, at about the halfway point between the West and East end of the dwelling. Can anyone recommend a particular, compatible unit, preferably affordable and tidy? Or, alternatively, is there another approach I can take that uses my existing router signal and makes it more usable at the more remote parts of my home?

zippyt 01-06-2008 01:54 AM

Antennas like to be up high ,
run some cat 5 to the second floor or the attic , put your wireless router up there , you SHOULD be able to get MUCH better recption from there .

IMHO

Elspode 01-06-2008 02:07 AM

I've considered that, but it is problematic.

zippyt 01-06-2008 02:12 AM

Why ??
Think in terms of closets that lign up from floor to floor ,
in side walls are generly not insulated , thus you can sneek a wire thru them , drill a hole in the top plate , and in the bottom plate , and fish a wire thru .

tw 01-06-2008 07:04 AM

Quote:

Originally Posted by zippyt (Post 421960)
Why ??

Many fear rather than ask zippyt's question. I routinely install some Cat5 cables in widely spaced locations throughout the building. A WiFi router can be located at any of these ethernet port when necessary to have the rare access out in the yard, or in a rarely used room.

So why is a signal trashed? Before solving a problem, first undestand the 'whys' behind a problem. For example, using the Dell signal strength meter (don't wast time using useless five bars), I could see where signal dBs dropped only in three feet. Turns out, the concrete foundation beneath the floor at that three foot region ate WiFi signals aggressively. An ethernet port was located behind a cabinet and a WiFi router connected there; mounted in the trough atop that cabinet where router was unseen. Wifi covered the rest of the house.

In another house, massive heat ducts, chimney, and bomb shelter in house center region meant no WiFi on one side could provide a strong signal to the other. Mounting the Wifi off to one side in house center(again using the Dell signal strength meter software) found a spot that covered all locations. Ran an ethernet cable to that location and located a wifi router there.

Running attic wires is easy - especially if the house has a chimeny. That chimeny means a hole exists all the way to the basement.

Meanwhile, those electric boxes with no back (sold in Home Depot and Lowes) make it real easy to mount ethernet ports or run ethernet wires in most every wall. The hole being large eought to also drill holes down to the next floor and to reach inside walls to catch wires.

BTW, do not use extension cords to power a router - if you have respect for fire. Router is typically a permanent device that requires a properly wired outlet. A most powerful tool is that signal strength meter that can report dBs for Wifi signals. Meter makes it easy to find blind spots where Wifi signals will intemittently dissappear. Meter also provides experience to learn what does and does not destroy Wifi signals.

My experience is that a Wifi signal will pass through two cinder block walls for up to 50 feet with a marginal signal of -80dB. Not to be confused with another type of block - cement block.

Ibby 01-06-2008 09:16 AM

wow, TW, this is a side of you ive never seen before...

’s kinda scary, really.

tw 01-06-2008 09:33 AM

Quote:

Originally Posted by Ibram (Post 421980)
wow, TW, this is a side of you ive never seen before...

What does that mean?

SteveDallas 01-06-2008 09:43 AM

Tw, could you recommend a useful signal meter? (Preferably one that doesn't cost an arm or a leg.)

richlevy 01-06-2008 09:53 AM

Ibram, TW is an engineer, either professional or lay, so it shouldn't be surprising.

That being said, I have to ask one question. Did TW build the bomb shelter or was it already in the house when he bought it? If it was already there, was it a selling point?;)

BTW, I was in a local game store a few weeks back when they had their Christmas sale. I picked up 6 or 7 foot lengths of used Ethernet cable for about a buck each. When I got them home I found out they were CAT 6!

I am once more reminded that, except of computers modeling weather or the stock market or looking for aliens, it appears to be gamers who use the most processing power and demand the best hardware.

This might explain why I get fragged so often playing Day of Defeat on my $199 Compaq.;)

tw 01-06-2008 10:32 AM

Quote:

Originally Posted by SteveDallas (Post 421985)
Tw, could you recommend a useful signal meter? (Preferably one that doesn't cost an arm or a leg.)

There really is no useful 'dedicated' signal meter that is inexpensive. But Dell owners can download one in software that works great.

The meter must select one Wifi station and only report dB numbers for that station. It also should provide signal to noise numbers AND historical information so that changes over the past few minutes can be compared to other events; especially when the human is over there making those changes.

Clodfobble 01-06-2008 11:35 AM

A completely different option... We were having problems getting a good enough signal to our downstairs MythTV box (long story short: we have a homemade TiVo-ripoff machine running Linux, and a second slave box downstairs that can stream recorded programs off of it so we can watch either upstairs or downstairs, and while our wireless signal was plenty strong enough for internet throughout the house, we would occasionally get buffering problems in the streaming TV signal.)

Mr. Clod's solution was to use an Ethernet-over-power box, which I had never heard of before--basically it's a little box that directly plugs your wireless router into any power outlet, and then a companion box is plugged into whatever outlet is near the item you want to get a signal to. The signal goes throughout the electrical cables in your house, no need for any additional wiring. It's not truly wireless per se, since you do have to be plugged into a nearby power outlet, but it's great for fixing that one spot in the house.

Elspode 01-06-2008 11:35 AM

I use Netstumbler on my computers...

http://www.netstumbler.com/

If you have a laptop, run this, and move the laptop to different locations to model your signal strength variations...

tw 01-06-2008 12:50 PM

Quote:

Originally Posted by Clodfobble (Post 422007)
Mr. Clod's solution was to use an Ethernet-over-power box, which I had never heard of before--basically it's a little box that directly plugs your wireless router into any power outlet, and then a companion box is plugged into whatever outlet is near the item you want to get a signal to.

Ethernet over power is akin to a previous technology called X-10 Controller. X-10 works great in some places and is problematic in others. Furthermore things like plug-in protectors and some appliances can 'eat' the signal. If located on circuits powered by opposite phases, a 'signal shorting block' (forget the correct name) may be required in that breaker box so that signal will transfer to circuits powered by that other phase.

Signal strength can be fine and yet not enough to overcome intermittent noise pulses. IOW the signal is fine for asynchronous communication such as web surfing. But real-time communication (including Skype) would suffer from the periodic noise bursts. Yes, a neighbor's WiFi also could be noise to your Wifi connection.

Another testing tool is to use "Ping -t xxx.xxx.xxx.xxx" to watch connections to that clone Tivo IP (xxx) address. Over an hour, every ping should be without loss. Same test on the Wifi connection could also be informative on the 'Ethernet on power' connection. And could be used to help locate something that was interfering with the Wifi connection (ie microwave oven).

Hardwired ethernet cable is a sure solution. Ethernet on power is a 'try it; you may like it' solution. However Wifi should have been more reliable if signal strength is so good that even running a microwave nearby does not cause signal loss. (Microwave ovens use the same frequency as WiFi.) Some tools and experiments to better understand what you have.

classicman 01-06-2008 12:55 PM

FWIW - the microwave at my parents eats their phone signal completely. To the point where the call is lost. That's on their "land line" cordless phone system.

zippyt 01-06-2008 04:20 PM

Running attic wires is easy - especially if the house has a chimeny. That chimeny means a hole exists all the way to the basement.

BUT fire codes have a stand off distance from chimneys,fire walls( fire proof walls to contain a fire) as do heating and cooling ducts.

what I was talking about was running wires thru closets that lign up from floor to floor ,
or if'n your feeling Gungy you can run said wires in side interior walls ,generally no insulation , but some time there are cross braces (:mad: :mad: )
Or if all else fails you could run some pipe on the out side wall , this is a LAST resort as it costs more ( pipe , fittings , paint , sealer , etc,,, )

Kitsune 01-06-2008 08:13 PM

Quote:

Originally Posted by classicman (Post 422020)
FWIW - the microwave at my parents eats their phone signal completely.

Same used to happen to me on the old 900MHz spread spectrum cordless.

Our new, overpowered, microwave eats the WiFi, here, completely. I need to change the channel on the router in the hopes that it might give it a bit more robustness, but I think we're out of luck for the most part. My old Powerbook completely loses connection, while Choco's Macbook Pro somehow survives it, barely.

steambender 01-07-2008 12:52 AM

Wi-Fi Propagation
 
like TW said, 802.11 Wi-Fi runs at the same frequency as your home microwave. The earliest versions are designed to co-exist with it, as most microwaves pulse at 60Hz, half cycle, so 50% of the time they're off, and the network would use those intervals.

I don't know if 802.11g, etc sticks to that, or maybe new, stronger microwaves changed to full wave...I've also never compared the legal leakage levels allowed for microwaves to the typical minimum required wi-fi receive levels, I should, it might be interesting to know how much interference to expect.

As far as propagation, absorption and shielding...Wi-Fi wants to go in a straight line...it'll bounce off metal if you need to make a bank shot, but unobstructed line of sight is what you want, and never get. That's why antennas work better high up, just as already suggested - better line of sight.

...Wi-fi wavelengths are about 4", so they'll sneak through gaps in metal that are bigger than an inch or so. they'll get blocked by metal ducts, foil backed insulation or low e glass windows (often have a transparent metallic coating to reduce solar load). they should go around small pipes and wires. They get absorbed by concrete, ceramic tile, wood and drywall. they fade with distance faster than lower frequencies, all in all, pretty tender stuff.

my linksys wireless access point has two antennas on swivels. It uses diversity reception techniques by exploiting the fact that two independent paths will experience different scattering as they bounce around the house, and so one of the two should arrive in better shape...it's very effective for time varying impairments like people walking around. yes, your body. a big conductive sponge to Wi-Fi.

Sometimes it helps to make sure that the two linksys antennas are pointed at right angles (one vertical, one horizontal, or both at 45 degrees). signal path scattering is also polarization dependent, and the little rabbit ears are polarized linearly with their orientation. that diversity trick, again.

if the access point is at the end of the house in the basement(?) and the access point antennas are removable, for a few bucks you could try a directional antenna aimed at the rest of the house...why waste signal in a direction you're not using?

whatever you do, don't forget your tinfoil hat. double ply is best!

steambender 01-07-2008 01:02 AM

I also heard a neat trick for getting networking and audio wiring installed in an existing house...central vacuum installers are expert at cheaply installing 1 1/4 (?) inch hoses in your walls, which are then dandy for snaking wires through...

tw 01-07-2008 08:08 AM

Quote:

Originally Posted by Kitsune (Post 422067)
Our new, overpowered, microwave eats the WiFi, here, completely. I need to change the channel on the router in the hopes that it might give it a bit more robustness, but I think we're out of luck for the most part.

Changing channels will not help. For all those Wifi channels, in reality, they overlap. Basically is only three separate channels - both ends and the center channel 6. They are all 2.4 Ghz. They share the same frequencies with many cordless phones, and other electronics - which also answers classicman's post.

Even XM working in lower 1.x Ghz frequencies can suffer interference if the antenna is located within 5 feet of the oven.

802.11a uses a different frequency from most other appliances (except some cordless phones). 802.11n should be more robust making interference less problematic. Netgear Rangemax was recommended previously due to its greater number of antenna configurations. Three more possibilities.

However in most every house, running an ethernet wire to another location is made so easy (but laborious) using things like the open space that goes from basement to attic alongside the chimney, those open back electrical boxes sold in Lowes and Home Depot, and, well, its amazing the number of tricks that alarm, telephone, vacuum, cable, intercom, and electric installers all have. Any can run provide holes for wires quickly. Running wires through walls is easy which is why I think poorly even of running exposes wires inside closets - another solution that makes running wires even easier. Difficult part is figuring where the drill bit will come out the other side. Thrill is when the drill bit emerges.

And then we have this miracle compound - spackle.

Kitsune 01-07-2008 09:38 AM

Quote:

Originally Posted by tw (Post 422162)
Basically is only three separate channels - both ends and the center channel 6.

Ah, that sucks. I thought we'd had better luck on another channel, but it was really more due to the previous underpowered oven.

Running wires isn't an option for us in an apartment, so we're simply going to have to continue to time the reheating of dinner to not interrupt cellar posts/network gaming/etc, etc.

classicman 01-07-2008 11:03 PM

Quote:

Originally Posted by tw (Post 422162)
Changing channels will not help. For all those Wifi channels, in reality, they overlap. Basically is only three separate channels - both ends and the center channel 6. They are all 2.4 Ghz. They share the same frequencies with many cordless phones, and other electronics - which also answers classicman's post.

Please answer it again - My parents are looking to get new phones.

Quote:

Originally Posted by tw (Post 422162)
And then we have this miracle compound - spackle.

LOL - spackle is your friend :right:

steambender 01-08-2008 01:09 AM

cordless phones & microwaves
 
Classicman...

microwave ovens operate at 2.54 GHz, same as Wi-Fi and some home cordless phones. There are other choices of frequencies for cordless phones, I saw some 5.8 GHz ones at Costco last week. They are far enough away in frequency that they shouldn't be interfered with by the microwave. There are also the old standby 900 MHz phones, which came out before the 2.54 GHz ones.

Each time a new frequency band is made available, and the chip companies make cheap silicon to support, people are conned into the new "better" frequencies. But all the sexy features don't matter if you get stepped on by another transmitter, deliberate or not.

classicman 01-08-2008 08:37 AM

So the microwave is operating at the 2.54 GHz - no doubt there? The problem is obviously on when the microwave is on. Therefore, if they buy a 5.8 GHz phone there will be no issue?

glatt 01-08-2008 09:40 AM

Quote:

Originally Posted by steambender (Post 422420)
There are also the old standby 900 MHz phones, which came out before the 2.54 GHz ones.

Our old 900 MHz analog Panasonic phone is dying. One of the buttons is getting sticky and isn't working right. We bought a new one, I think in the 5.8 range, digital (maybe even spread spectrum?), and the reception was FAR worse than the old one, so we returned it. There was static within the same room as the base station. Direct line of sight. Is there anywhere you can get these old 900MHz phones? I haven't seen any in stores. I'd love to just be able to buy a new matching handset. I love this old phone.

Clodfobble 01-08-2008 12:03 PM

Fry's has one online. It's advertised as for old people though. :)

Quote:

with large easy to read buttons, a large red flashing call indicator, Caller ID, and an extra loud ringer, this phone is great for those loved ones that are hard of hearing.

glatt 01-08-2008 12:16 PM

Old people, eh?

It is analog, which is what our current one is. The thing just works.

steambender 01-08-2008 12:20 PM

cordless phones
 
yeah, microwave ovens are 2.54 GHz, but they're also unstable, sloppy, dirty and huge from a radio perspective. They're great at heating food. sort of like trying to have a conversation next to a jackhammer.

I can't give you any specific advice about which phones work better, a lot of it depends on the choices made by the phone designers (and the accountants). The name brands do usually try to avoid embarassing themselves.
even though I do this kind of thing for a living, when it comes to consumer stuff, I'm trolling the reviews on amazon and epinions, just like everyone else. I usually wait for 6 months or so before jumping to a new technology or until I read that something really kicks ass, or I can't control my geek urge.

glatt, the 5.8 GHz phones not working in the same room sounds really wrong..were they a reputable brand? (2.4 GHz spread spectrum panasonic in our house, but we are not frequent phone users, so don't encounter much interference). Ebay might be your best friend for finding replacement 900 MHz phones...Digital might work a bit better than analog, properly done it works a lot better.

Don't put all of the blame on the phones. over time, microwaves get their doors slammed a lot, and the RF shield gaskets may loose their coverage so that the oven leaks a bit more. The safety standards are pretty convervative, so there's little exposure risk (as life risks go) unless your teenager decides to turn the oven inside out in an effort to make a death ray and zap the neighbors cat. But the increased leakage levels will play havoc with other users of the same frequency band (Wi-Fi, cordless phones, wireless video cameras, RC control links, etc)

there are cheap ($30) microwave leakage detectors on the internet, but I have no idea how reliable they are. I personally use stuff like that at work, but we spend a lot of money on it, and it still takes experience to acheive professional results (that I'm willing to bet my paycheck on, anyway)

glatt 01-08-2008 12:35 PM

Quote:

Originally Posted by steambender (Post 422513)
glatt, the 5.8 GHz phones not working in the same room sounds really wrong..were they a reputable brand?

They worked, but when you walked around in the room, and turned and stuff, there was occasional static. Unacceptable, as our current 900 MHz analog phone works just fine. We can even go outside in the back yard with it, around 100 feet away. I wish I remembered the brand. I think it was Uniden, but not sure. Bought at Staples.

None of this is an emergency because we have a corded phone on each floor, but it's frustrating when the "new and improved" technology isn't as good as what it is replacing.

aimeecc 01-08-2008 12:47 PM

We had to move the wireless router and cordless phone base from the bedroom office to the 1st floor exercise room (which is directly below the bedroom office). We can now get both signals from anywhere in the house. Not sure why, but it worked. I think the cordless is 900 MHz, and I bought it maybe 3 years ago.

tw 01-11-2008 10:40 PM

Quote:

Originally Posted by steambender (Post 422420)
Each time a new frequency band is made available, and the chip companies make cheap silicon to support, people are conned into the new "better" frequencies.

The FCC (due to limitations by a more important group – ITU – because international standards are more important than domestic ones) has provided only some narrow frequencies for general, low power, unlicensed operation. These frequencies are called ISM (if I remember correctly: Industrial, Science, & Medical). For example the 900 Mhz is something like 918 Mhz plus/minus maybe 10 Mhz. Other frequencies are 433 Mhz, 5.8Ghz, 24 Ghz, and now 60 Ghz. 60 Ghz has recently taken interest in the movie industry where range is limited (apparently) because oxygen absorbs the signal; therefore preferred for wireless operations where one does not want remote monitors recording those signals. Manufacturers are only just starting to design commercial silicon for 60 Ghz - once only the domain of the military.

Some higher frequencies are also approved for ISM use - but the hardware is not yet available. It is not new frequencies made available. Limitation is getting hardware to work at those 'state of the art' frequencies. Reason for 'hyping' these new frequencies are so many appliances already using those lower frequencies. For example, add Blue Tooth to the list of 2.4 Ghz users. No wonder the 5 Ghz portable phone is now preferred.

Many of these ISM frequencies are not standard throughout the world. Wifi 2.4 Ghz is standard on the first (so called) eleven channels. Whereas the US allows ISM for 11 channels, I believe the Japanese (overlapping) version is a wider band (14 channels). BTW its 2.45; not 2.54 Ghz. 900 Mhz is available only in limited regions such as North America and a few other nations.

How to get your enemy to waste $1million. Setup a microwave oven so that it operates with the door open. Microwave ovens output massive power as to appear to Hellfire missiles as a radar site. One only loses a microwave oven. But the enemy wastes a $1million missile trashing that oven. Welcome to the Balkans.

classicman 01-12-2008 12:10 AM

Quote:

Originally Posted by tw (Post 423778)
How to get your enemy to waste $1million. Setup a microwave oven so that it operates with the door open. Microwave ovens output massive power as to appear to Hellfire missiles as a radar site. One only loses a microwave oven. But the enemy wastes a $1million missile trashing that oven. Welcome to the Balkans.

Ahhh human ingenuity eh? What a wonderful thing.

richlevy 01-12-2008 12:24 PM

Quote:

Originally Posted by steambender (Post 422135)
yes, your body. a big conductive sponge to Wi-Fi.

Hey, who are you calling a sponge?:mad:

Quote:

Hooray for Captain Spaulding / The African explorer / 'Did someone call me schnorrer?'
Yiddish sponge humor.

Short of turning the receiving room into a Faraday cage with one end open towards the transmitter (The Cone of Silence Approach), switching to transmission by electricity might work (have not read a lot of reviews), or switching cordless phones, wireless cards, or just stringing cable is the best bet.

Wiki has a great article on wireless. I did not realize that the old 802.11a and the upcoming 802.11n were 5ghz, and the upcoming 802.11y is 3.7 ghz.

In theory you could use 802.11a and sacrifice range for less interference.


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