“Sensitive retro look radio capable of receiving signals from middle wave and short wave band.
This radio receiver is capable of receiving all MW and SW bandwidth, and can also operate as an SDR receiver, so with the help of PC and appropriate software we can decode many different types of signals.
At the input we start with a potentiometer of 1 k ohm, it is the RF attenuator. The next circuit is the preselector, switchable to the MW and SW ranges. Tuning of the preselector is done with a potentiometer. The tuning voltage is stabilized by 4 LEDs but of course you can also use a 6.8 V or 8.2 V zener diode. The two transistor RF amplifier increases the sensitivity and prevents also that Local Oscillator signals from the mixer are leaking to the antenna input. This would cause a lot of hum. The mixer is a well known NE612 (or NE602, SA602, SA612).”