Indicated for adjustment in transmitters for the 11-meter band, this circuit with analog meter was found in the Radio Electronics magazine of January 1978. The circuit does not use a power supply.
This circuit was found in a Poptronics of the 90's. The components can be changed to the desired...
This version of a call-fish is from 1981 using, for this reason, a 90 V battery that is no longer...
Found in a 1969’s Electronic Design, this circuit operates in a narrow range of voltages....