Pat,
The losses are due to the DIELECTRIC of the coax, thus, would most certainly
be a factor, however, as has been pointed out for only a foot or so to get
thru a wall or window, this would wash out, and the mismatch would be taken
care of by the associated transmatch used to tune the ladderline fed dipole on
any band.
You could use a single twinax (two conductors inside a shield) coax cable,
which is lower impedance than the typical twin lead/ladder line, again because
the transmatch tunes out the reactance of whatever it sees between it and
antenna.
Another method is to use capacitive plates glued to both sides of the window
glass, and transfer the ladder line to inside this way. You would simply need
a capacitibe disk plate, of reactance 1/10 of the nominal line impedance, or
45 ohms/30 ohms range, for typical ladder line/twin lead.
Hope this is helpful,
Stuart K5KVH
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