"Roy Lewallen" bravely wrote to "All" (06 Apr 05 22:10:02)
--- on the heady topic of " VF, low-loss line, high-impedence line - =
relationship"

RL From: Roy Lewallen
RL Xref: aeinews rec.radio.amateur.antenna:28064

RL Do you mean that lines of approximately 377 ohms impedance are more
RL susceptible to the environment than 200 or 600 ohm lines? In what
RL ways? Why?

Since a portion of the EM field in open wire line is free to travel
outside the conductor into the environment then we may safely assume
there is an exchange between the environment and the conductor. If the
impedance of each is approximately the same then there is less loss in
the interface between the two. It has to do with the reflective
coefficient where the energy is returned. You will note 300 ohm open
line has less loss than 100 ohm open line.


RL The loss in coax is a trade off
to achieve stability.

RL Coax is more stable than open wire line? Does open wire line drift in
RL some way?

It is susceptible to ambient humidity and proximity to conductive
objects (birds, snow, rfi). That is a source of drift in practical
terms.

A*s*i*m*o*v

.... No individual raindrop ever considers itself responsible for the flood