Although you probably have done so already, try an Internet search for "lowfer" groups. They do exist. I have a copy of a LF "scrapbook" that was published back in the 1970's, but it's in storage and I can't get the title of it right now, but it's something like "The Low Frequency Scrapbook". There also have been several articles in hobbyist mags on the subject. I think that Don Carr also had a book out on the subject.
Dean