1. abdulsamad4321

    Thread Starter Member

    Nov 24, 2013
    Please tell me relation between frequency and free space loss. Which frequency is better to trnasfer data 900MHz or 1800MHz?
    Thank you.
  2. BR-549

    Well-Known Member

    Sep 22, 2013
    Ok. Co = speed of lite. Eo = electric permittivity. Uo = magnetic permeability. In free space......Co = 1/EoUo. Which frequency you use will depend on local and regional environment and topology.
  3. dougc314


    Dec 20, 2013
    read up on "free space path loss" on Wikipedia, there is an equation.

    At first glance people think that for higher frequency there is more loss, and therefore higher frequencies can't work as well. If you are constrained by antenna gain, that is so. However antenna gain is based, generally, on the relative (in wavelengths) of an antenna's effective area, which is similiar to its actual area if the antenna is designed correctly. So, at higher frequencies a certain size antenna will have more gain then at lower frequencies, and that can make up the frequency "penalty" However if you need antennas with a certain directivity, say omnidirectional then yes, path loss increases with 1/F^2. (But the required antenna gets smaller)

    To answer which band is better depends on many things other than just free space path loss.