There is not a command-line utility supplied with the 3945ABG cards that allows the radio to turned on and off. As you mention, however, the Intel(R) Mobile Platform SDK can be used to do this if you don't mind writing some code. You do have to install the Intel(R) Mobile Platform SDK which includes a runtime service that must be started for this to work. You don't, however, have to install the Microsoft .Net CLR if you simply write native C++ code. If using C#, the .Net CLR is required. If using Java, then a supported JVM is required. Also note that at the time of this writing this feature works on Windows XP, but there is a problem on Windows Vista that prevents it from working correctly.
