Last updateFri, 22 Feb 2019 1pm

COMPUTER CORNER: How far can your Wi-Fi reach? It depends!

A question I get a lot is “What’s the maximum range of my Wi-Fi?” 

Much to the frustration of the person asking the question, I often answer that question with, “It depends!”  Because there are many variables that must be factored in, it is simply not possible to give a simple one-size-fits-all answer correct for all circumstances.

Probably the best example is to imagine two people sitting next to each other on the same couch.  One has a smart phone and the other a laptop computer.  The laptop user is able to get a stable Wi-Fi connection to the internet while the smart phone user right next to him may be getting nothing at all. Among the many variables involved in this example is that the wireless radio transmitter in the laptop is probably a lot more powerful than the smart phone.  Phones typically have much less powerful radios in order to achieve longer battery life.  So in this example the Wi-Fi range is fine for the laptop, but the weaker smart phone needs to move closer to the Wi-Fi transmitter.  Same Wi-Fi, two different answers.

Another situation I have seen is that a client has a wireless access point sitting in her living room that has large windows overlooking a patio, beyond that a swimming pool, and beyond that a large lawn.  The client found that she could carry her smart phone as much as 50 meters away from the router, all the way to the lawn, and still get a usable Wi-Fi signal.  However, when she walked only 3-5 meters from the router in the opposite direction the signal was lost.  Why?

The reason is that when she walked north she was quickly in a location closer to the wireless router belonging to her next door neighbor than to her own router, and the signal from next door was stronger, thus interfering with her own wireless.  When she walked away from her neighbors past the patio, past the pool and to the lawn, there were no other competing wireless radios there.  In fact there was a large pasture beyond the lawn, and unless any of the cows grazing there were using Wi-Fi, the client could possibly have used her smart phone 100 meters away in that direction.  So what is the range of her router?  Answer: three meters to the north and possibly 100 to the south.  Same Wi-Fi, two different answers depending on which side of the transmitter you are standing.

And a statement I hear repeated often is, “It used to work just fine!”  Sometimes the reason a Wi-Fi installation worked well in the past but no longer does so is because there was an apartment building constructed across the street and a new house built next door. Each apartment has its own Wi-Fi access point and the new house next door has wireless with two repeaters.  Suddenly there are many Wi-Fi access points competing to use the same radio spectrum, and when they have to share, then everybody sees slower speeds.

Charles Miller is a freelance computer consultant with more than 20 years IT experience and a Texan with a lifetime love for Mexico.  The opinions expressed are his own.  He may be contacted through his web site at SMAguru.com.

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