This receiver has no IF amplifier. This detector has high impedance output. The audio amplifier has 11dB gain. The capacitor of the gate is used not to make self oscillation. I will explain about transmitting time.
Audio signal is amplified by the audio amplifier.
The signal is limited by the two diode D1 and D2. The oscillated frequency is modulated by the audio signal. This signal is amplified by the transistor amplifier. The output power becomes 5mW. I made QSO with my friend living 6km distance from my house with this machine for one hours.