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Everything About WiFi

The Computer Corner

By Charles Miller

A few months ago in this column; I made reference to an incident where someone’s daughter had run up a cell phone bill of hundreds of dollars one month by surfing Facebook while using cellular data, and that using WiFi would have been free. Another question often addressed here is why WiFi connectivity has such a limited range and is so unreliable. I am going to attempt to explain both situations, but understand that doing so here in 500 words precludes an in-depth analysis.

The radio spectrum is defined as that part of the electromagnetic spectrum at frequencies between three kilohertz and 300 gigahertz. Signals transmitted at various frequencies behave in different ways, and some radio frequencies are simply better than others. The lower the frequency, the greater the distance, the higher the frequency, the smaller the volume of data that can be carried. The Earth’s atmosphere, rainfall, terrain, and buildings affect different frequencies differently. Obviously police, fire departments, airlines, and others need very reliable communications, so they got the good frequencies.

The radio spectrum was completely allocated long ago when AM/FM/shortwave radio, television, emergency, military, government, and private industry claimed blocks of radio frequencies. Today, wireless communications are increasingly being used to provide broadband access to the Internet to smart phones and portable devices. This has put a strain on the radio spectrum that was already sold out decades ago.


“Sell” is the operative word here. Governments auction off the right to use parts of the radio spectrum for commercial use and the good-quality frequencies demand a high price. Cell phone companies pay billions of dollars to buy the right to use those radio frequencies that provide the best and clearest communications.

What is left over is the “unlicensed band” of frequencies that for one reason or another are not much good. Some radio engineers irreverently refer to these as “garbage frequencies.” They are the radio frequencies that are prone to interference, are very short range, or just do not work well. They are called “unlicensed” because anyone can use them without the need to purchase them or to get a government license to operate radio equipment on those frequencies. And these are the radio frequencies you and I use when we employ WiFi to access the Internet.

So, you might ask, is it not possible to have reliable wireless Internet access everywhere in your house by using a better radio frequency? Absolutely so! Using cellular data rather than WiFi can provide that. The cell phone company had to pay a high price to license those radio frequencies, and you can use them by paying your cellular provider for a cellular data plan.

That solution can be really expensive (see paragraph one), so most of us prefer to make do with what is available for free, and that is the ersatz 2.4 GHz band used by WiFi. This is very limited range, prone to interference, and does not penetrate concrete walls. It is a lousy frequency, but it is free. So, with an understanding of its limitations, WiFi is the best low-cost solution for most people’s home wireless connectivity needs.

Charles Miller is a freelance computer consultant, a frequent visitor to San Miguel since 1981 and now practically a full-time resident. He may be contacted at 415 101 8528 or email FAQ8 (at)


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