26 Jul 2017
Yesterday I had an enquiry about amateur VLF. I referred him to https://sites.google.com/site/sub9khz/ which has lots of data on what I did in the past. There are schematics of the receivers and transmitters I used as well as details from others. Most of my experiments were with "earth mode", although I also received several European amateur VLF stations by radiation. For receive you do not need a large antenna. Even on "earth mode" transmit the power and antenna requirements are quite modest.