Saturday, March 15, 2014

Calculating Wavelength If Frequency Is Known

I get this question a lot. It’s not exactly phrased this way though. Typically it’s along the lines of “What’s the wavelength of the WiFi signals in my home or office?

Good question and a pretty simple calculation! I do realize with a quick Google search you can look the value up but….. that takes the fun out of it J

First, let’s define wavelength. Electromagnetic radiation is sinusoidal in nature and wavelength, represented by the Greek letter lambda (λ), is a distance measurement usually expressed in meters. Wavelength is defined as the distance in meters of one sinusoidal cycle as illustrated in the figure below.

Most WiFi signals run at around 2.4 Giga Hertz (GHz) or 2.4 Billion cycles per second!

Now, in you home or office, you’ve likely got a lot of other wireless devices (microwave, ovens, cordless phones, baby monitors, etc) operating in this same 2.4 GHz frequency range. In the WiFi world, the 2.4 GHz WiFi signal range is divided into 11 channels and channels can be selected when setting up a wireless network to avoid other devices transmitting in the same frequency range.

Ok – back to our question – what’s the wavelength? Here’s how we do the calculation:
12.5 cm is approximately 4.92 inches and...... that's your wavelength.

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