I've recently been asked to install some wireless networking kit at a very large, old country house.
I visited the house yesterday to perform a site survey and take a look at the requirement. The two key places which require wireless access are literally in opposite sides of the house. Being a very old building, there is no structured caballing and the route from room A to room B would be very difficult to cable.
I have set up many wireless LANS, using single router/ap combos and also larger WLAN's using multiple APs caballed back to a router/switch. I haven't until now configured a WLAN with additional antenna and I'm looking for guidance and advice.
If I was to purchase Buffalo access points and attached a directional antenna, would this likely penetrate multiple walls. The other idea, is for me to point the antenna out of the window, towards the other side of the house.
I know it is hard to say how well an antenna will perform, without knowing distances and the construction of a property, but are they effective at extending signal, where the line of site is broken with walls/glass or other obstacles.
Any suggestions or advice would be greatly appreciated.
Without a doubt directional antennas work & help penetrate. Here they've proven appreciably better than omni's of same db, amazing difference. especially with directional on both ends ,,, which has been outstanding here. unless of course I want a virtual line of site to pass through the metal lathe&plaster walls here, then things are just really weak.
Wood, brick, lath-n-plaster, construction? One floor, two floors, big windows, small windows? Totally flat or on a hillside? Basement? Attic? Online photo? Numbers? Details?
Am I being sufficiently subtle? There's no such thing as a universal solution that will work for all types of building, construction, layout, topology, and topography.
Is the building floor plan squareish, or elongated? How far are the two key places at opposite ends of the house?
I'll take your word for that, but I've found that buildings with outside plumbing are very easy to cable. I try to sell the owner on wiring the house for cable TV, telephone, bunglar alarm, thermostat, intercom, etc at the same time. See comp.dcom.wiring for hints.
You've led a sheltered life. Welcome to wireless hell. The real secret to successful wireless is to get a clear line of sight. NLOS (non line of sight) solutions are at best a crap shoot. Shooting
*THROUGH* a building or house is one of the best ways of guaranteeing repeat visits to "optimize" the wireless. You might be able to make it work today, but as things move around the house, the path will change. I strongly suggest you avoid shooting through a house. If you must do so, then place the access point at one end of the house, attach a fairly large panel antenna (14dBi gain 35degree beamwidth) and point it towards the other end of the house. If possible, shoot it down a hallway. Your level of success will be limited by the number of walls the signal has to smash through. I've found 3 to be about the limit. If the walls have aluminum foil backed insulation, give up now.
2.4GHz doesn't penetrate walls very well. It sneaks through cracks, hallways, windows, and doorways. As a rule of thumb, one wall is usually possible, 2 walls is a potential problem, 3 walls is totally unreliable. Again, you can probably find a location at opposite ends of the house that will work, but you will not be able to keep it working at that location.
Well, if the house layout allows such a system (i.e. dog-leg or L shape), then by all means, this is the way to go. Shoot through the windows. However, if the windows have been retrofitted with aluminized mylar for energy efficiency, it won't work at all. Incidentally, locating the access point outside and shooting through windows is the preferred way to do hotels and apartments, where inside clutter would block the signal. I did a large mansion long ago by installing the access points in various outside locations (including a tree) and pointing the antennas toward the large glass windows. Biggest problem was the gophers chewing up the waterproof CAT5.
Yep. If structure attenuation were your only problem, it would be easy to calculate. The real problem is reflections. There's no guarantee that your path through the building maze will go via a single stable path. It will bounce around and create multipath, the eternal enemy of reliable wireless. Try to think of this as an exercise in increasing the fade margin.
Run the wires if possible. Otherwise, try illuminating from the outside. Do NOT bother trying to shoot through the building unless your site survey shows a very strong signal or you have RF transparent inside (glass?) walls.
Old houses tend to have at least 18" thick walls. Trying to get through the walls sounds unlikely to me unless the doors line up. Antennas outside the building in line of sight. Networking over mains, provided it isn't a different mains phase in the two areas. Data rates are limited at present over mains but may be acceptable.
Thanks to everyone for their advice and recommendations, in response to Jeff's questions:
The building is over three floors, including the attic. Walls are of brick construction and the windows are small, leaded lights.
A very rough plan can be seen here -
A picture can be seen here -
The distance from office A to office B is approx 25 meters
There may be a straightforward route for some CAT5 caballing, if run external to the property. There is already a PABX phone system which runs between the rooms, so routing may be simpler than originally thought.
I have considered Ethernet over mains, but as it is a very old house, the wiring may be separate circuits and I'm certain of the quality.
Thanks for this advice, it makes me even less likely to install a pure wireless solution. The last thing I want to do is install a solution which is unreliable and will require additional visits to troubleshoot.
Thanks again for your advice, I'm investigating the structured caballing option, with localized AP for individual areas.
I don't think a single wireless access point is going to work. 2.4GHz does not like water or anything with water in it. Masonry, brick, and vegetation are full of water to varying degrees. Same with asbestos or crushed rock in the roofing tiles. 2.4Ghz is not going to penetrate even one wall, much less the 3 or more required to do this with a single access point. You're only chance is going through a window, some of which appear to be clogged with vegetation.
You might have a chance if the interior construction is of light wood (i.e. pine). 2.4Ghz will go though about 2 such walls. Watch out for wallpaper with aluminum foil backing.
I scrounged for data on materials attenuation in the past and found:
that the attenuation for brick varies from 2 to 8 dB depending upon who did the testing. Apparently, there are some rather drastic variations in test and construction techniques.
Looking at the layout, my guess is that you'll be shooting through at least 2 brick walls (not counting inside walls) no matter the alignment. Your only chance is if you have a common pair of windows where each office is directly visible from the other. That doesn't appear to be the case.
I've had terrible luck with powerline networking. Too slow and subject to interference from appliances. On of my friends did that and found that his connection was comatose when running the laundry machines.
If you have existing telephone cabling, it might be possible to use them for ethernet connectivity. I've done this successfully with 25 pair cable at 10baseT (10Mbit/sec) rates. It will NOT work at
100Mbits/sec and all connections must be forced to use 10Mbits/sec. The catch is that it MUST be dry, good quality, paired cable and is probably limited to about 25 to 50 meters per run.
I've also done it using 10base2 (Cheapernet) over CATV coax cable.
run is about 300 meters or RG-6/u.
Topology is somewhat of a nightmare because it must be arranged as a "star" rather than a "bus". That means all your phone cables and wires have to come together at one location. That's possible in an office building, but usually difficult in a home where the phone wiring is arranged as a bus.
It is possible to use wireless through walls and obtain a reliable system. However, I have some evidence to the contrary. Current, I'm replacing wireless with wired in approximately 10% of my installations due to reliability issues. I have an other wiring job to replace wireless in 2 days. The problem is usually interference from other wireless users. That may not be an issue here as it appears that there are no neighbors. Working with desktops is always a problem because they don't move. A laptop can move around if there are changing propagation conditions (i.e. moving furniture). That's not so easy with a desktop. I've found users constantly juggling the position of their wireless devices to accommodate the latest changes.
A site survey, also known as "try it and see how it works" is fairly simple. If you have a good solid strong signal throughout the building, then it will work. If it varies all over the place, then it probably will be a problem. A fun test is streaming media content with a small buffer. If the music sounds intermittent and full of dropouts, so will the data.
That might work if the inside construction is light weight. Good luck.
Thanks for your assistance, you seem very knowledgeable in this area! We are most likely going to run CAT5e to the areas which require wireless access, then install AP's.
As you seem to have installed many sites, I was curious to find out what Wireless AP hardware you normally use? I've used Buffalo kit in these scenarios previously, but wondered what else is available on the market, possibly the type of devices used in a more commercial environments?
I see that Cisco kit appear at the top of the ladder when it comes to commercial kit, but I wondered what manufacturers are in between and worth considering?
I haven't really done that many wireless installs. Most of what I do is repair existing installs, engineer complex systems, do some design work, play wireless consultant, and deal with WISP related issues. I also help setup and play policeman for a few coffee shop style hot spots. I rarely get to choose the hardware as it is already in place by the time I get involved. I have no real preference as to brand or model and tend to end up with mixed systems. Well, actually I do prefer Cisco 350 series with separate routers, but my small customers can't afford much of that.
In a classic example of do as I say, not as I do, our neighborhood wired and wireless LAN consists of all the mixed junk that was returned or rejected by my customers. The major specifications are that it not have a fan that makes noise and that it be cheap (or free).
For conventional business systems, look at Proxim Orinoco and Sonicwall TZ170 series.
For office buildings and distributed hot spots, look into wireless switch vendors such as Aruba (HP), Airespace (Cisco), Trapeze (3com), Chantry (Siemens), and Symbol:
a centralized management and monitoring system is a basic requirement for any complex or large system. I'm online right now looking at erratic >70% packet error rates for one wireless access point. Looking at the RRDTool history graphs over the last few days, something new appeared on Tues afternoon. My guess(tm) is that someone installed a cordless phone in the warehouse and planted the base right next to the access point.
Wireless switches offer this type of central management. However, the problem is that once committed to a wireless switch vendor, you're also committed to a homogenous system consisting only of the vendors proprietary hardware and solution. If they drop the ball, you end up replacing everything. The central switch box also presents a single point of failure so be prepared to deal with backup issues. Also, some of the wireless switch vendors have blundered into the direction of wireless mesh networks, which I consider an RF polluting abomination and should be avoided if possible.
Of course, everything you buy today will be obsolete tomorrow, so plan ahead somewhat. WiMax might also be a suitable solution when the cheap hardware finally arrives.
Just talked to the customer with the >70% error rate. Nice new Plantronics Bluetooth cordless phone adapter sitting literally on top of the Cisco 340 wireless access point. Moved a few feet apart and the error rate is down to about 5%. Try doing that without history, statistics, and remote management.