Owen,

Are you aware of programs -

RJELINE2, RJELINE3, for balanced pair lines,

and COAXPAIR, COAXRATE for coaxial lines ?

These are based on exact, classical transmission line formulae and
will tell you all you could wish to know about behaviour of
transmission lines versus any complex termination from open circuit to
short circuit. No approximation of critical parameters.

However, in the coaxial case, dielectric loss is an input quantity.
;o)
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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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