VLF upconverter

Amateur VLF transmissions demand very narrow bandwidths, high stability, long integration times and special (free) software. By contrast, commercial or government VLF signals are often strong. These stations usually have high power and very big antennas.

To receive commercial or government broadcasters a simple upconverter is fine. An example of one is my design.

For amateur VLF signals this is almost certainly not suitable. Most amateur VLF signals are seen on a PC screen rather than heard.