There is no such thing as a feedline which will not
radiate/pick up signals. Even a solid copper outer
cable. The difference is only in the degree of
leakage, but the least leaky cables are those with
solid highly conductive outer conductors and the
lowest velocity of propagation.
A short lay length will increase leakage, so tightly
twisting two coaxial cables together will
significantly (>>10dB) increase leakage over those
same two cables running parallel with no twist. The
leakage of two balanced cables is not significantly
different from that of a single cable. You still have
the same problems, but removed to the receiver
location from the antenna.
73 Roger
VE3ZI
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