On Mon, 26 Dec 2011 14:52:22 -0800, DEFCON 88 wrote:

I've seen pictures (which I can't seem to find on the internet) of old
AM
broadcast antennas consisting of multiple parallel wires strung between
two towers on the rooftop of a building. These were typically located on
top of a hotel, with the broadcast studio in the hotel.

I've seen pictures of antennas like that strung between the masts of
old steamships. Folded dipoles. The high-impedance feedline (ladder
line) fed the center of the center wire. Instead of a single additional
wire connecting the ends of the center wire, a bunch of parallel wires
were used, separated by several circular spreaders.

When you make an antenna with a large-diameter radiator, it is inherently
more broad-band than just a wire. The multiple parallel wires created the
equivalent of a radiator with the diameter of the circular spreaders.
In those days, antenna tuners were standard equipment anyway.