Useful American sub-9kHz experimental VLF site

VLFradio.com is a most interesting site. Among the stuff there are the results of some induction communications tests with a 90m circumference TX loop out in the desert away from man-made interference. Using just 0.5W a range of 1 mile (1.6kms) was achieved at 1.8kHz and with higher power up to 2 miles (3.2kms). These signals were copyable by ear, so further still would be possible with weak signal techniques. Also on the site lots of recordings of these tests as well as other VLF noises and man-made transmissions