It actually consists of a tunable field strength meter. The circuit is of an old documentation and the circuit must be tuned to the frequency to be monitored. The circuit offers the option to use a headset.
Found in a documentation from the 90s, this circuit limits and amplifies a voice signal in the 800...
This circuit was found in documentation from the 90s. The operational amplifier is NE5514, which is...
We found this circuit in the August 1970 issue of Radio Elecronics magazine. It uses the CA3018...