Frequency

Value to Enter:

Check the button next to either 2.4GHz for 802.11b/g or 5.8Ghz for 802.11a. If you're calculating for a different frequency band, enter the frequency as either Megahertz or Gigahertz and check the appropriate button.

Significance of This Value:

Different frequencies experience different degrees of attenuation through obstructions (walls, trees) and in the atmosphere (based on humidity and altitude.) The Connect802 Wireless Network Path Link Budget and Antenna calculator needs to know the frequency band in order to take these factors into consideration.

Background and Technical Perspective:

As the frequency of a transmitted signal increases the degree to which the signal strength will be reduced by obstructions increases. An 800 MHz cellular phone signal can pass through several concrete walls and penetrate the interior of some buildings but a 45 GHz point-to-point microwave link has trouble penetrating a strong rainstorm. Consider the fact that frequency and wavelength are related to the speed of light (wavelength=c/F where c=speed of light in m/s and F=frequency in hertz). The following table shows the relationship between wavelength and frequency:

It can be seen from the table above that penetration of a 1-inch obstruction requires more signal cycles at higher frequencies. At higher frequencies the electromagnetic wave is required to interact with an obstruction many more times than at lower frequencies. Consequently, if an 800 MHz signal experienced a 94 dB loss while traversing a particular transmission path the 45 GHz signal would experience a 130 dB loss.