This squelch circuit is placed at the input of the single receiver audio amplifier stage. Its purpose is to silence background noise. The circuit is from an 80's documentation.
This photoelectric circuit from a 1960 publication uses a 6.3 V electromechanical counter, common at...
We found this circuit in a magazine 73 from the 90's. It is a circuit indicated for radio-amateur...
) This circuit uses two 4046 CMOS PLLs to produce a modulated signal of good intensity. The MOSFET can...