I have an old Hy-Gain 18AVT/WB-A 80M through 10M vertical antenna that is roof mounted about 20-25 feet (two stories) above ground. I currently have four sets of five wire rotor cable as the radial system. The lengths are as described in the 18AVT manual. The fifth set is a second 40M length. I need to replace the radial system due to age. I was interested in cloning the Butternut RMK II roof mount radial system. This is the unit that uses 300 ohm twin lead notched at several places. I have seen a couple of write ups on this system but nothing definitive enough to reproduce the set. I have seen some dimensions but I still have a few questions. One question is that the end of the uncut twin lead leg is mated with the other twin lead leg 3' from the end. I am assuming that the 3' leg that continues on to the insulator Of the notched and longer leg) is not in play at any time, is that correct? Another question is, I was wondering if do I use the butternut dimensions or do I try to use the Hy-Gain manual dimensions which vary a bit. Hy-Gain gives you 37' for 40M, 18' 7.5" for 20M, 11' 10.5" for 15M and 9' 10" for 10M. The Butternut dimensions, when adding the legs together at the proper time vary from the above dimensions. Is the difference simply each manufacturer used different resonence frequencies? I also wondered if I could build a set of twin lead radials designed like the Butternut RMK II but cut to lengths for the 30, 17, and 12M bands. I was thinking that with a total of 8 radials (four like the RMK II and four for the 30, 17, and 12M bands, I could cover everything. I am trying to keep the number down because I will need to just drape some of the radial legs over the edge of the roof as well as I am trying to keep the antenna system discrete. The RMK II dimensions are in the later section of the Butternut Tech Notes found at this website. http://www.bencher.com/pdfs/00366IZV.pdf Any comments or advice regarding what I am planning to do would be appreciated.