[klondike98]

A signal tracer is a tool to help track down which stage of your radio is not working correctly.  If you inject a modulated rf signal from your signal generator into at the antenna of your radio, and if all is working well, you should hear the audio tone from the generator (usually 400 hz or 1000hz tone) coming out of your radio's speaker.  If you don't hear the tone, you can use your signal tracer with its probe to test the grid on each of the stages from the antenna to through to the speaker.  The stage where you stop hearing the tone means you just went past something that is not working correctly.