Hello Walt

Having just done a quick Internet search I have come up with an
interesting site:

www.qsl.net/sv1xv/lf.htm

The site is called 'the world below 535 kilohertz'

It has a load of links which I don't have time to explore at present.

One mention is of the   LFCA - Low Frequency Club of America - these
bits of information may help you further.

73
--
David W Wood