How do you make a longwave radio receiver?

Question

I have future plans in making a radio receiver that receives frequencies on the longwave bands (LF) to receive beacons, European broadcasts, and also Lowfers transmissions. I also
want to use the popular NE-602 chip for the mixer and oscillator
like every other receiver. The problem is that I don't know what I need to get down to the longwave (LF) frequencies from 144 kHz to 519 kHz. I just wish that some electronic kit vendors would make a kit that does this. I have a loop antenna and also a outdoor antenna for my current longwave receivers. Would a
2.5 mH coil work with the 365 pF capacitor? I would like to learn more about how to make one. If there is AM broadcast there is a chance for LW broadcast reception also.

Answer 1

The formula for the frequency a radio receiver is tuned to is f=1/(2times pi times sqrt(Ltimes C)) where L is the inductance of the tuning coil in henries and C is the capacitance of the tuning capacitor in farads. f is in hertz. So all you need to do to convert a medium wave AM receiver is to replace the tuning coil with a much larger one. You can even build a VLF receiver at home cheaply to pick up the VLF (around 12 KHz) transmissions to submarines which can travel through sea water.

Answer 2

Long Wave Radio Receiver

Answer 3

There are a few VLF ELF clubs you can join. Typically anything below 500KHz is considered LF. Navy vessels uses LF as well, the power output on the antenna is dangerous.