Symmetrisches Doppelnetzteil (liefert zwei (bzw. vier) symm. Spg.)

There are quite a few interestjng transmitters in the frequency band from 1.8 to S.4 MHz: ships, aircraft, amateu rs_ and ~roadcast transmitters in the tropics. W1.lh the aid of a simple converter this band can be received on a normal MW receiver. The converter described here gives a certain amount of gain, so that it can be used with practically any normal receiver - even one with relatively poor sensitivity. FET TI is included in a source follower circuit to reduce the loading of the LC tuned circuit at the input. The limiting amplifier in IC I is used for the oscillator circuit, and the product detector is used as a ixer. The output circuit (L4, CI0, Cl I) is tuned to approximately 1.7 MHz (175 m). This is the frequency that the MW receiver is tuned to; it should be at one end of the MW scale. If necessary, C 1 0 and C 11 can be increased slightly to accomodate receivers with a shorter MW band.