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.

VLF upconverter

VLF upconverter

Some years ago I was looking for a simpłe VLF upconverter (to receive SAQ) and came up with the simple circuit shown in the link. This was later improved by HB9DAO. The improved design is also shown.

If you want a simple introduction to VLF or LF listening these circuits may give you some ideas. It would not be suitable for serious amateur VLF use over any distance when high dynamic range, long integration periods, and very narrow bandwidths are pretty essential.  It is ideal for reception of commercial VLF signals and time standard transmissions.

See https://sites.google.com/site/g3xbmqrp3/vlf/vlfconv .