I have always been fascinated by this portion of the spectrum. A fun fact I found is any signal below 3Khz is unregulated by the FCC. Also, I came across AA5TB's excellent page on the topic of VLF,etc.: http://www.aa5tb.com/longwave.html For those who are interested too, check out the INSPIRE experiment: (warning:turn down speakers, loud lightning sound when visiting site): http://theinspireproject.org/ INSPIRE is an experiment to receive and analyze natural VLF sources. His comments are quite in line with what you've posted so far. I also remember finding a page that claimed several records of QSOs at different frequencies. Do you have a link to that effect? Thanks for posting this! I may pull together a small ground antenna and try out that experiment with local AM stations!!