> Some seem to use 'not quite normal' coax cable as part of their
> overall signal shaping. ie not lowest loss and maybe even custom loss
> characteristics.

I believe one trick that has been done is to use a resistive centre 
conductor, to help reduce reflections in the cable. I have seen scope probe 
cables where the inner insulation has an 'oversize' hole, and the centre 
conductor appears to be a fine nichrome wire that does a zigzag down the 
large hole. The hole would appear to be about 10x the wire diameter. 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist