Monday, October 24, 2011

2.4GHz: is it all it’s cracked up to be?

We recently received this intriguing article from Dave Horvath and invite you to read it and then join in the discussion.  
A substantial number of unexplained crashes of radio control model airplanes on 2.4GHz frequency prompted me to write this article on the so-called “interference free” radio control systems on the 2.4GHz band.          
The electromagnetic wave spectrum is subject to the immutable laws of physics.
The propagation characteristics of the 2.4GHz wavelength and the environmental effects of this frequency are more complex than on the 72MHz band. To better understand this, we have to look at the electromagnetic wave spectrum where 72MHz band is in the broadcasting region and the 2.4GHz band is in the microwave region. It is easier to see the huge difference between 72MHz and 2.4GHz frequencies when we convert 2.4 gigahertz to megahertz. Now it is 2400MHz versus 72MHz. When frequency increases, wavelength decreases. Therefore, the 2.4GHz wavelength is shorter and closer to visible light on the electromagnetic wave spectrum. Since visible light is also an electromagnetic wave, 2.4GHz wavelength behaves more like visible light and travels in straight lines until it is reflected, deflected, diffracted or absorbed. Reflection and diffraction will create interference. When parallel rays of light are reflected by a concave mirror, it greatly increases the intensity of light at the focal point. A parabolic dish antenna works the same way for a 2.4GHz electromagnetic wave. Since we cannot focus a high gain directional parabolic dish antenna between our constantly moving model airplane and our transmitter, we have to use an omnidirectional vertical antenna system which has much lower signal intensity.  
Read the rest here.

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