Lest there be some confusion, although power companies twist primary lines,
they are putting BPL on Secondary lines that are not twisted, and therefore
radiate like blazes.
Even if the power companies were intentionally putting BPL on the HV
primary lines, the twist on those lines would not be sufficient to
maintain balance at HF frequencies. The twist on HV power transmission
lines takes several miles to go through the whole twist sequence. This
is a small fraction of a wavelength at 60 Hz, and so it can help to
balance the capacitance with respect to ground on the three hot wires,
at 60 Hz. At HF the twist could actually make the situation worse,
making the transmission line act as a giant colinear array with
fantastic gain in some directions at some frequencies.
DE N6KB
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