Here is my version of a "squealer" for an audio output from the R2LC. It consists of an inverter/level shifter and a 555 timer chip. The frequency range isn't really broad, but it is enough to hear changes of RF signal strength. I am also using my meter in voltage mode for a digital readout via wireless video. The loudness potentiometer is 500 ohms. The battery's positive terminal (via a switch) is connected to Pins 4/8.
I needed an acoustical baffle for the rear of the speaker, so I just decided to stick the circuit board inside the a truncated pill bottle that had already donated its closed end to another project. It is powered off the 9V battery I am using for the R2LC.
I wanted to swap out the Harbor Freight meter for one with display illumination so that my video camera's image would be clearer, but wouldn't you know it, HF didn't have a single one in stock yesterday! When I go to Camarillo Wednesday, I will go to the main HF headquarters to pick one up.
So now my configuration is complete - test receiver, squealer, meter, wireless video, and a 'scope and one of my Track Signal Strength meters to monitor the output of the Base.