A Portable Qrp Cw Amateur Transceiver For 2200 Meter 136 Khz Ham Band

  
It's frequency can be adjusted by a varactor diode which performs very good frequency stability. The receiver section is a direct conversion type and utilizes a RF amplifier. The output section has a LM386 audio amplifier ic which is connected to a 3.5mm male jack for external speaker or headphones.