Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Near field path loss with attenuation

  1. Sep 27, 2012 #1
    1. The problem statement, all variables and given/known data

    I have a 2 wireless cards with a power output of 0dBm, two 5dBi gain antennas, and a 30dB attenuator connected to each antenna. I need to figure out what the path loss will be in this scenario, so I can therefore determine the maximum distance possible between the antennas before they can no longer receive each other's signal.

    2. Relevant equations

    I know path loss in dB:

    L = 20 log_10(4 * π *d / λ)

    this one I can use to find the max distance once I know L, but I don't know how to find the path loss due to the attenuation in the first place.

    3. The attempt at a solution

    I know attenuation is:

    = 10 * log_10(power out/ power in)


    30 dB = 10 * log(power out/ odBm)

    How can I find power out from here?

    And how could I use that in the path loss equation?

    Thank you for the help.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted