[amsat-bb] dc to antenna preamplifier through coax

I have a recollection of seeing a description of a method to insert dc through the coax to a antenna preamplifier but can't locate the article. A mind is a terrible thing to lose. If you know where I can find the article please E-Mail me at alozias@att.net . I am considering using this method for a TV antenna preamplifier.

Thanks - Al - N7EQF