I sincerely appreciate the trouble people take on this list to spread knowledge to a dumbo G3 with thinking circumscribed by 807's . I am here more for that than for knowing where to buy a TSxxx mark
I still feel guilty that I managed to bluff my way on this subject in the RAE test in 1949 when I was a physics sixth former and ' knew everything ' If a man from Ofcom turns up here and says "demons