Change Airport signal strength
You can make 5.6.1 work with on Mavericks with a workaround, as detailed here: 

http://coreyjmahler.com/2013/10/24/airport-utility-5-6-1-on-os-x-10-9-mavericks/


  The issue with AirPort Utility v5.6.1 under OS X 10.9 Mavericks is
  that a system file upon which AirPort Utility relies was updated in
  10.9 and that update broke backwards compatibility with AirPort Utility v5.6.1. The file in question is Apple80211 in
  /System/Library/PrivateFrameworks/Apple80211.framework/Versions/A.
  Replacing this file with the older version allows AirPort Utility
  v5.6.1 to be run under 10.9, but only via Terminal (i.e.,
  double-clicking it will not launch it, it will throw an error).
  
  However, there is a way to get around this issue by importing the older library into AirPort Utility v5.6.1 before running it. That is
  what the new solution, downloadable, infra, does.