[TenTec] Re: parallel lines rated by losses

[rohre@arlut.utexas.edu (Stuart Rohre)]

OK, without being too long, look at any good antenna text and you should
find the fact that the higher the impedance of a feedline, the lower the
current and thus the resistive losses.  In a ranking of feedlines, lines
with a lot of dielectric around the conductors are more lossy than air
insulated lines, and in between are the semi-air spaced ladder lines.

Thus, Most losses in feedline especially unmatched:  Coax 50 ohm, then 75
going toward lower losses:                                          Twin
lead 300 ohm
                                                                  Ladder
line twin lead 300 ohm
                                                                  Ladder
line parallel    450 ohm
Lowest loss                               Open wire types of parallel lines
600 ohm or

higher
Less current, more air around conductors=lowest losses
73, Stuart K5KVH