Found in a documentation for radio amateurs from the 90s, this circuit is suitable for RF measurements in transmission systems. The potentiometer must be of a special type.
WWV is the prefix for the United States' time and frequency patterns station. These signals can be used...
This is 4-input audio mixer using an integrated circuit 741 and two more operational amplifiers....
This circuit is from a 1965 General Electric manual. It uses components from the time that admit...