Sunday, February 13, 2005

Speed Fluctuation from 11 to 5.5 to 2 to 1

Many people have told us that their Wi-Fi Internet connection slows down all the time and even drops them. This is a very frustrating (to put it mildly) situation. What causes it, and what can you do about it?

By Design: The first thing to understand is that this is the way Wi-Fi works, it is designed to re-negotiate the connection speed as needed. Remember 56k modems? They rarely, if ever connected at 56k. If there was noise on the line, they might connect as low as 28.8. And, that's where they stayed, even if the noise cleared up. With Wi-Fi, 11Mbps is the top speed. If your computer is close to the Wi-Fi Access Point (our antenna) they negotiate their connection at the highest speed. If something interferes with the signal it will renegotiate the connection to a lower speed like 5.5 or 2Mbps in order to maintain the connection, but it will continually renegotiate and get back to the higher speed when it can.

Distance from the Access Point: The closer you are to the Access Point (the Coach Connect antennas) the better. Most USB wireless adapters only promise 11Mbps if you are within 150 meters of the Access Point with line-of-sight. If you are further away, or there are obstructions (like other RVs) it will try to negotiate a lower speed and still keep you connected. From our experience a network connection speed of 5.5 is usually sufficient for a comfortable web-browsing experience. We've even seen 2 or 1 speeds successfully browsing the web, but it's unusual. When the speed drops that low, you're in danger of losing your network connection altogether. You need to get closer, or remove the obstructions. You probably can't ask the other RVs to move out of the way, but you may be able to provide 'line-of-sight' to your adapter by getting it up high. The photo at the right shows what one resourceful RVer did by buying an extension for their USB cable and attaching the adapter to a pole. I hope they brought it in when it rains! If you can't get closer, or remove the obstructions, there are currently several high-powered external antennas on the market that can improve your ability to connect. More on that in another article.

RF Interference: A Wi-Fi network is a 2-way radio system operating at 2.4 GHz. Other things that operate at 2.4GHz will interfere. Microwaves and 2.4GHz cordless phones will affect your network connection. I was amazed the first time I saw this; I was browsing the Internet just fine and, all of a sudden, my network connection icon popped up a message saying 'low or no connectivity'. I turned to Jim and said, "what's going on?" He said, "well, I just turned on the microwave." Sure enough, as soon as the microwave stopped my connection came back on, full speed. Jim tells a story when he was visiting a customer and the customer's wife walked by their computer area talking on a cordless phone. He could watch the signal drop completely out of sight. It came back when she hung up the phone. So, we know that microwave ovens and 2.4GHz cordless phones affect the network connection. What we don't know is how far away this can happen. It could be that microwave ovens in the RV next door can make your signal fluctuate.

Repairing the Connection: If you're using Windows XP, you can right-click on your wireless network connection icon and choose the 'repair' function. If you're not using XP, the command might be called 'rescan'. In either case, this is a great thing to do any time your connection is slowing down. It forces the network connection to reconnect and try to negotiate a higher speed. It almost always improves your connection's performance. It's kind of like being on a phone call that gets so full of static, it's hard to have your conversation. You might say, 'let's hang up and I'll call you back'. When you call back, you almost always have a better connection.

Spyware: I hope you're still reading, because this may be the most important part. Spyware on your computer can cause the same symptoms as being too far away, or having RF Interference. Let me tell you the story of how we discovered this. We were working with a customer who complained of fluctuation in her connection speed. She said it would go up and down from 1 to 5.5, back to 1 and then drop her altogether. She would sometimes get 11, but that was rare. Most of the time it was low and she was really getting frustrated with getting dropped when she was in the middle of a transaction on the web. First we verified that she was using a good USB adapter (built-in or card adapters rarely have what it takes to connect to a long-distance Wi-Fi hotspot) - she was. Her symptoms really sounded like she was just too far from the Access Point, or there was too much heavy metal between her computer and the Access Point. She was in a Park Model, so moving to another site was not an option. We had no choice but to close her account and refund her money. She obviously couldn't use the system.
So we thought.
After a couple weeks on dial-up, she called us back asking if there was anything she could do to boost her computer's antenna power so she could use the system. We told her about a special antenna we had been testing, and she was all for it - 'whatever it costs'. So, we tested it at her place - that's me holding the pole with the high-powered antenna at the top. It helped a little, but not much. Her network speed still fluctuated. This was not what we expected. Other places we had tried this antenna, it made a BIG difference. We were scratching our heads.
She let us take her laptop computer 'home' with us. We took it to our motorhome and tried to use the Wi-Fi there. We were pretty close to the Access Point, our computers were online, at 11Mbps all the time. Her's still did it's fluctuating thing! So, we did our standard 'cleanup' procedures, including running the new Microsoft Anti-Spyware software. We only found 4 problems on her computer, but they were the nasty kind. Worms that install 'backdoors' on your computer and monitor activity on certain ports. You would normally expect an anti-virus program to catch these, but many of them actually disable the anti-virus programs. Microsoft's anti-Spyware caught these.
When we returned her computer to her, it worked great. She was browsing reliably and her network connection maintained the 11Mbps speed. That was several weeks ago now, and she tells us it's still working like a champ.

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