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900MHz vs. 2.4GHz - Flying in wooded areas

Discussion in 'DJI Ground Station' started by StrikeTeam, Jul 29, 2014.

  1. StrikeTeam

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    Hi all,

    I want to buy a GS but I'm not yet sure for what frequency's.
    I will be flying in areas with trees and I would like to know what your experience/opinion is regarding Abstruct-Tree Attenuation ( loss in (signal) intensity of any kind of flux through a medium) on 900MHz versus 2.4GHZ/5 GHz.

    I have read (https://www.tapr.org/ve3jf.dcc97.html) attenuation loss for trees is in the order of 0.1 dB/m at 500 MHz, 0.2 dB/m at 1 GHz, 0.3 dB/m at 2 GHz and 0.4 dB/m at 3 GHz. So it looks like there wouldn't be too much of a difference between 900MHz and 2.4GHz if I'm dealing with a highly dense area of trees (2dB loss at 900MHz and 3dB loss 2.4GHz for every 30 feet of trees) . Do you agree?

    If there's not much of a difference and I will anyways need to elevate the antenna to make it within LOS then I'd think it's better to stay with 2.4GHZ. There's its advantages over 900MHZ with higher gain antennas and lower cost amplifiers/antennas etc..

    Thanks for your input!
     
  2. StrikeTeam

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    I see IEEE published many studies on this.
    I can't read them because it is blocked by a paywall

    e.g. http://ieeexplore.ieee.org/xpl/logi...ore.ieee.org/xpls/abs_all.jsp?arnumber=575471

    Multi-Components Mobile Propagation Model of Park Environment

    This work extends a previously published theoretical propagation model to a park environment and compares measured and computed data for different types, size and shape of vegetation or trees. Horizontal and vertical attenuation values of leaves, trees and branches, as a contribution to total attenuation are separately obtained and effects of each element to total attenuation are assessed. Finally a comparison is done between 900 MHz, 1800 MHz and 2270 MHz. The difference in path loss between the three frequencies has been analyzed for park environment. The result shows that the loss from vegetation which depends on biophysical parameters is substantially higher for the higher frequencies.
     
  3. captej26

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    Re: 900MHz vs. 2.4GHz - Tree Attenuation

    wow