We always preferred a signal tracer since it is more passive. Those were typically just audio amplifiers with an optional diode in the input to demodulate RF.

Starting at the volume control was still a good idea. If you heard radio stations through the signal tracer, the RF section was fine.

The radio frequency (RF) signal generator market size will grow by USD 24.92 million during 2019-2023.

FAIRPORT, NY—Saelig Company announces the availability of Triarchy Technologies' VSG2G5C RF Vector Signal Generator—a cost-effective pocketable USB-connected RF signal source with capabilities ...

Enhances high-density relay matrix signal distribution application performances, throughput, and efficiency Superior RF Performance Wide frequency response from DC to 3 GHz ...