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Homework Help: Free-Space Path Loss Equation - finding the constant for d in km and f in MHz?

  1. Feb 3, 2013 #1
    1. Problem Statement
    Transform equation 1 into equation 2 to show they're equivalent.

    2. Relevant equations
    relevent equations.png
    *Please note that I added a subscript to each variable indicating the units.

    3. The attempt at a solution
    the attempt at the solution.png

    The highlighted constant shown in my attempt at the solution is supposed to be 32.45 according to both my notes and wikipedia http://en.wikipedia.org/wiki/Free-space_path_loss.

    Thank you very much!
  2. jcsd
  3. Feb 4, 2013 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    log(ab) = log a + log b
    log(abc) = log a + log b + log c
    log(a/b) = log a - log b.
    OK I see you already know that.

    I can't make out your writing but in your eq. 2, λm should = cm/fHz. Maybe that's where your problem lies.

    I would have started by converting the original argument of the log function into the units
    they want you to wind up with, but your way works too,
    Last edited: Feb 4, 2013
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