Wireless Interference: Smashup On Interstate 2.4

You just can't win in this unregulated wireless spectrum. If the network's not interfering with the phone, the microwave oven's interfering with the network.

Click! Click! Click! Thats the sound of my 2.4GHz Siemens Gigaset phone system when my 802.11b wireless network is nearby, especially in some parts of the house. I actually dont notice it so much, but people I talk to complain. My range on the phone and wireless network is also greatly diminished when both are operating.

Wireless comminication frequencies have moved up over the years for a variety of reasons, and the current hot zone is 2.4 GHz. All the wireless devices you want to use operate in that range. In theory these devices are supposed to know how to stay out of each others way, but try to use enough of them at once and youll find out otherwise.

And its not just wireless communications devices that make trouble. The biggest problem in a lot of houses is the microwave oven, which vomits electromagnetic interference all over everything within several feet of it. This can be a problem intermittently for the cordless phone, but less so for the wireless network in my case. I dont usually keep a node on that side of the kitchen.

My interim solution has been to buy a 900MHz phone. You may remember that 900MHz was the 2.4GHz of the mid-1990s. It was the new advanced feature that gave cordless phones better range, less interference, whatever is good about phones, they had it. They were certainly better than the first generation of cordless phones, which worked in the 46-49MHz range, where anything with a motor, from the garage door opener to the electric toothbrush will interfere.

Look up tech support on these devices and theyll tell you to keep your phone base station and wireless access point away from each other, but thats easier said than done. My access point needs to be near my other networking equipment, which is in my office. My base station is my primary buisness phone and in -- you guessed it -- my office.

Partly because higher frequencies are better in some ways and partly because 900MHz got crowded the FCC opened up the 2.4GHz range. Now we even have the 5.8 GHz range open; its where youll find 802.11a networks and a lot of newer, even more expensive phones.

So like I said, 2.4GHz wasnt big enough for my phones and my network. One of them had to go. An 802.11a wireless network is a possibility because I actually have the equipment left over from a networking book I wrote, but when I used it I found the range to be much less than 802.11b. The higher frequencies have better range out in the middle of the Sahara, but in a house with walls and other obstructions the picture is murkier. Talk to real engineers who work on this stuff and youll find them very reticent to give numbers for range of their products. The truth is that it depends on a large number of variables, too many to predict.

That meant moving the phone. The reason I bought the model I bought (the Siemens Gigaset 2420) was that at the time it was the only system that had multiple lines, multiple handsets, caller ID, and a bunch of other things. You can find a lot of phones with these features in 2.4GHz models now, and even a few at outrageous prices in 5.8GHz, but nothing like it in 900MHz.

So for now Im satisfying myself with a lesser 900MHz phone. It doesnt have caller ID, no multiple handsets, only 10 speed dials. But I can use the phone right next to my wireless notebook and not sound like a telegraph.

Security Supersite Editor Larry Seltzer has worked in and written about the computer industry since 1983.