This article appeared in the September 2006 edition of the Valley Vibration. It details three recommendations regarding wireless installations:

1. Rather than replacing a wired router with a wireless router, keep the wired router and add a wireless access point. Use a POE kit if necessary -- it will avoid having to find a power outlet near the access point, making it easier to place it in a central, above-eye-level location.

2. Always set up a WEP privacy key to keep outsiders out of your network.

3. Name your access point (SSID) with your street address so neighbors can identify you and negotiate channels numbers to minimize mutual interference.

4. Before turning on your wireless router or access point, find out what channels your neighbors are using so you can pick a channel that will have the least mutual interferance. Only use channels 1, 6, or 11. (Lucas Valley cable always does this for you on wireless upgrades, but it may need to be repeated if your neighbor goes wireless or changes channels. Some wireless adaptors have a site survey feature that shows the channel numbers of neighboring access points. If yours does not, you can try the free Net Stumbler program if your laptop runs windows and has a compatible wireless adaptor.)

The article recommends that the LVHA sanction a committee to assign all LVHA homes with a wireless channel.

Wireless - the Silent Cacophony

by Herb Drake, Lucas Valley Cable, Inc.

Nobody knows how many wireless networks are in our community. I recently took my laptop and some special software for a ride on Lucas Valley streets and counted 138 of them-and those are only the ones that overflowed onto the streets (I didn't drive up any driveways or cross any property lines). I imagine that new ones arrive every week, and the fact that so many of them can be detected on the streets makes it a certainty that their coverage extends to neighboring homes. And that creates the potential for interference-a kind of unintentional electronic warfare where there are no winners and where everybody loses. This article is intended to inform and assist those who already have a wireless network or are thinking about getting one. I'll be discussing interference and some of the other issues that need to be considered before installing a wireless system.

Having so many wireless networks so close together creates a cacophony of radio interference that can cripple many of these systems. Added to this mix of radio signals are cordless telephones, microwave ovens, and a number of other devices that share the unregulated piece of RF spectrum allocated by the FCC for these services. This electronic racket may be silent to our ears, but is a screaming din to wireless devices. As a user, all we can know is that our network mysteriously crashes every once in a while and then starts working again with no real hint as to why. Some have a wireless system that was working fine for years, but suddenly started working poorly when a neighbor joined the wireless bandwagon. Too often, the solution is to buy a more powerful access point. This is like the "noise wars" that we may have played as kids; two siblings will turn up their radios louder and louder in an effort to drown the other one out. In this case, however, the two opposing parties don't even know they are in a war and, in the end, the only winners are the salesmen who hawk ever more powerful access points.

Before looking at some of the issues affecting wireless networks, it might be a good idea to ask whether a wireless network is really a good idea in the first place. Personally, I won't have one. A wired network is far more reliable and secure than any wireless system and completely avoids the problems discussed below. A wired home network that always works and doesn't keep one up nights worrying about wireless hackers just may be worth the inconvenience of plugging a computer into a network jack. But for those who really enjoy the freedom of movement of the wireless laptop, the good news is that there are some things that can be done to moderate most of the problems.

Optimizing Coverage

Wireless networks begin at their "access point," the device that connects the laptops and other devices to the home network and gives them access to the Internet. Most Lucas Valley homes that already have wireless have their access point built into their router-that is, they have a "wireless router." And that is where coverage problems begin. Since routers are devices to which multiple cables connect, they tend to be at desk or floor level, buried behind clutter, or nestled between cabinets. Access points, on the other hand, work best when above eye level and centrally located. So the first recommendation for most wireless users is this: it is far better to purchase a separate access point and connect it to a wired router. Separating the access point from the router allows one to locate each in its optimum location. Adding a Power-over-Ethernet (PoE) kit is also helpful, as it allows the access point to be placed in a location away from a source of power; the PoE kit powers the access point over the network cable that runs between it and the router. This arrangement allows the access point to be located in such places as the top of a living room bookshelf, the top shelf of a hallway or bedroom closet, or high on a hallway wall. When placed near the center of a home, coverage tends to be even throughout the home. Were all homes to have good, centralized coverage, the problems of interference between homes would be minimized as well. So, rather than replacing your router with a wireless router, keep the old router and obtain a separate access point. If the access point will be located away from a power outlet, also obtain a PoE kit.

Some wireless users are reticent to have an optimally located access point because, after all, one needs to use a dreaded wire to connect to it. "I thought this was supposed to be wireless,", one customer protested to me recently! Well, the wireless part is between the access point and the computer, not the router and the access point. But with the PoE kit, you can get the wires down to an absolute minimum.

Legal Troubles and Privacy Concerns

A wireless system with sufficient power to cover the street and neighboring homes brings up legal issues. Not being a lawyer, I can't speak with authority in this area. But I have been told that a line is crossed when your computer tells you that it can find a neighbor's wireless connection and you click through to make a connection to it; that action is a violation of a neighbor's privacy unless you have specific permission. And that access leaves tracks in the neighbor's router. Perhaps more serious, however, is whether wireless users are risking the loss of their Internet connection by violating the terms of their ISP contract. It would be a good idea to review your contract, as most ISPs (including Lucas Valley Cable) prohibit the sharing of an Internet connection across property lines and have a right to disconnect non-compliant customers.

Surely, one can't solve this problem by tailoring wireless coverage to within one's property line-radio waves are too capricious for that! But it is generally agreed that one or both of the two most common methods of wireless privacy solves this problem. They also provide some insurance against those who might want to violate your privacy by invading your wireless system from the street. The two methods are Wired Equivalent Privacy (installing a "WEP key" in your access point and each of your computers) and "MAC address filtering" (listing the physical "Media Access Control" address of each laptop into a table in your access point.). Of the 138 wireless networks I found in my street survey, only 58 had WEP encryption. Some of the remaining 80 may have had MAC address filtering, but surely many were wide open "hot spots" that could be easily exploited by a neighbor or just somebody with a laptop parked on the street.

If you don't know how to set up privacy on your wireless network, consult your users' manuals. Most manufacturers make these manual available on their web sites.

Analyzing and Minimizing Interference

Wireless networking shares many traits with wireless telephones. The designers of the modern wireless 'phones quickly realized that the only way to accommodate thousands of simultaneous individual radio connections in areas of high population density without an interference nightmare was to use multiple, low-power sites so that each frequency scheme could be re-used. To accomplish this, they divided population centers into hexagonal "cells" that resemble the cells inside a beehive (that's why they're called "cell 'phones."). They discovered that, by having three separate frequency schemes, it is possible to arrange the sites so that no two adjacent cells share the same scheme. The only other requirement was to limit the power level of each cell site so that it did a good job of reaching customers anywhere in its own cell, partially illuminate the six adjacent cells, but have near zero illumination of cells outside of the adjacent cells. This latter requirement was necessary to allow the re-use of the same frequency scheme two cells away. Cell 'phones work because the coverage area of each site is carefully engineered to satisfy these two requirements-low level antennas and power levels carefully adjusted to be high enough, but not too high.

Wireless systems in a community like Lucas Valley present a very analogous situation. While each telephone cell site is assigned to one of three frequency schemes, each home in a community can be assigned one of the three non-overlapping wireless channels. Those channels are 1, 6, and 11. If you are on one of those channels, you cannot interfere with a neighbor using one of the other channels in this group. Unfortunately, some of the systems I found in my drive-by survey on in-between channels (e.g., Channel 2 or 5), which mean that they have the potential to interfere with two of the non-overlapping channels. So step one in minimizing interference is for everyone using wireless to pick one of those three channels. Which one? One not being used by any immediate neighbor.

I can see only two ways of accomplishing this. The first is to identify the neighbors who have wireless systems overlapping your property and coordinate channel numbers with each. To do that, you need to find out who your wireless neighbors are, and the best way to do that is to "name" your wireless system with your street address so they can find you and you can find them. The second way to solve the problem is to invite a LVHA committee to lay an approximation of a hexagonal grid on the community map and assign each home a wireless channel number from the 1, 6, and 11 group whether they are presently using wireless or not. If sanctioned by the Board, it is my hope that everybody would be willing to cooperate in such an effort for the mutual benefit that would result.

Once the channel number part of the problem has been solved, the next problem is to follow some of the other rules in order to allow each wireless home to have a good chance of success. That includes the use of a single access point at each home (that is, one channel per household-no second access points) and careful attention to coverage providing optimal coverage in each wireless home.

Using wireless may be a step forward in personal flexibility, but it does have some downsides. These can be minimized by a systematic approach to understanding and solving the problems. Proper attention to privacy measures, access point location and community cooperation should be able to calm the "silent cacophony" and make wireless networks reasonably trouble-free.