Yes I'm learning the basics in RF circuitry in my ET course. The junction box question was more a separate question that I lumped in, sorry. I was told the signal maintainers on a railroad work with junction boxes a lot. By the way I'm really impressed with my ET course, it is extremely thorough. I mean the first part alone is 40 books, and 40 exams with just an incredible amount of lessons. I can see why you need a real education to do this type of work, and not just on the job training. I realize as I go that there is absolutely no way to really do this work without an education. Its actually pretty fascinating to be honest.