Peter O. Brackett wrote:

Modern technology such as xDSL is in wide use on literally millions of
lines with extremely complex Zo world wide and has been made available
for very feasible prices! This is not academe! Such devices are very
practical, not academic, and have been developed within the industrial
community by thousands of practicising Engineers not academicians. A
lot of this very advanced work has been "exposed" in the Standards
Committee arenas of ETSI, ITU and ANSI. And so I consider this wide
exploitation of extremely complex Zo lines to be practical Engineering
and technology and not academic.

Fair point, Peter. Although the theory behind xDSL is still the province
of academic journals, this is a good example of theory into practice.

Even if we don't ever use the information within amateur radio purposes,
we may well have to deal with problems when it hasn't been implemented
correctly; so yes, we do need to know something about it.

The theory of transmission lines with complex Zo is where the two areas,
xDSL and amateur radio, touch and maybe overlap just a little. All the
more reason for writing an article!


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek