Vlf Converter

Posted on Jul 24, 2012

The VLF Converter can be used to pick up signals for the general coverage of shortwave receivers. A number of unusual signals

Vlf Converter
Click here to download the full size of the above Circuit.

can be heard on frequencies below 15 kHz. This converter will convert frequencies from 0 to 250 kHz to 3 500 to 3 750 kHz so that the LF- and VLF-band segments can be received on an amateur or shortwave receiver that covers 3 500 to 4 000 kHz, Signals from a short whip antenna (8 to 10 feet) are coupled through low-pass filter L1/L2/C2/C3 to RF amp Ql. Q3 mixes these signals with a 3.5-MHz signal from Q2 and associated components C4, R5, R4, and 3.5-MHz XTAL. L3 is an RF choke that presents an inductive load to Q3. It should be resonant somewhat above 3.5 MHz when placed in the circuit. An adjustable coil of about 30 to 100 should be sufficient. The converter output is taken from the emitter of Q3 through C6.

Leave Comment

characters left:

New Circuits



Popular Circuits

Arduino multi-mode lamp with soft touch switch
Electronic Buzzer with IC timer NE555 circuit diagram
switch mode power supply design of current load sense circuit
stepper motor controller
Fox Hunting
Infrared automatic faucet circuit diagram
Family Kara OK lights 5GM168 a control circuit diagram