Today, a new tower and a new metaphor. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
Try this: Towers have always
been metaphors for communication. Lighthouses tell
of a rocky shore. Minarets tell the hours of
prayer. Steepled churches, visible for miles, were
the Medieval communication centers. The towering
elevators of the grain-growing towns of the
19th-century Midwest were spaced out along the
railway tracks, announcing each whistle-stop.
The Tower of Babel is our metaphor for failed
communication. Different towers tell of different
things in every age. Today, skyscraper towers,
power-line towers, all reach upward. So which tower
speaks to us -- and what does it have to say?
Architect Michele Bertomen studies the view from
the sprawling Long Island Expressway and offers her
answer. What she sees are antenna towers. Let's see
how they work.
AM radio goes out on fairly low frequencies -- from
half to 1.7 megahertz. AM wavelengths run from 200
to 600 meters. Long waves like that bounce off the
ionosphere and travel very far. With the right
radio you can pick up signals from China.
My FM station, KUHF in Houston, airs at 88.7
megahertz. It gives a far clearer signal than AM,
but its wavelength is only 11 feet. It travels in
an almost straight line. Our antenna has to sit on
a huge tower -- 1640 feet high. The signal reaches
a horizon some 60 miles away. Beyond that radius,
it rapidly dies out.
Television, radar, telephone, and FM radio all ride
on microwaves, and they all follow approximate
line-of-sight paths. So a new metaphor for
communication -- the microwave transmission tower
-- rises among us.
You see those tall, spindly ladders of structural
steel everywhere these days. They're oddly
unimposing, considering their size; and they've
crept into our midst almost unnoticed.
Michele Bertomen drives Long Island and records 17
towers, most of them over 300 feet tall. They're
modest compared with ours, but still longer than a
football field. They're slim and delicate --
festooned with antennas. They have the odd grace of
any really good piece of design.
And the metaphor is more powerful than ever today.
Our lives are wed to these great communications
beacons. Poet Robert Coffin catches their meaning
when he describes light houses:
If men could still be holy anywhere,Whether these towers bring a measure of
holy quiet, or a torrent of messages, into our lives
is ours to decide, of course. In the end, the way we
use the metaphor -- remains our choice.
It would be in towers such as these
That line the coasts with lamps and warn the ships
The holy towers of silences.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds