Dakota Datebook

Tall Towers One

Wednesday, December 8, 2004

On this date in 1966, The North Dakota Board of Higher Education accepted title to the KTHI-TV tower from the Pembina Broadcasting Co. The move put the gigantic tower into the hands of the state, gave Pembina Broadcasting a tax break, and allowed UND and NDSU to add a powerful antenna for broadcasting educational television programming.

The KTHI tower was – and still is – the tallest, man-made, land-based structure in the world. The only structure that is higher is the water-supported Petronius Platform in the Gulf of Mexico. The North Dakota tower was completed in 1963 about three miles west of Blanchard, southwest of Hillsboro. It now transmits for KVLY, an NBC affiliate in Fargo.

The tower held the record for highest man-made structure for eleven years until, in 1974, a radio tower in Poland surpassed it by 57 feet. When the Polish tower collapsed in 1991, the KVLY mast again went hit the top of the list.

An 11-man crew assembled the tower in 33 working days – thankfully with no casualties. The cost was half a million dollars. Its broadcast area is roughly 30,000 square miles – that’s an area about the size of Hawaii, the District of Columbia, Massachusetts, New Jersey, and Connecticut put together, with a thousand square miles left over.
The original call letters of KTHI were specifically chosen for H-I, referring to the height of the mast, which is 2,063 feet tall. Once it was completed, the Federal Aviation Administration imposed a limit on further construction of this altitude; no structure in the United States can now legally exceed the KVLY tower’s height.

There are many interesting facts and figures about this structure. It’s taller than the Washington Monument, Eiffel Tower and the Great Pyramid combined. It contains two million feet of steel, guy wire strands and elevator cable, and the structure, along with its guy anchors, takes up 160 acres of space.

The total weight of steel used in the tower is 864,500 pounds. The total length of guy wires is 40,125 feet – that’s 7.6 miles long. The elevator cable used in construction of the tower is 7,870 feet, and the 9,000-pound antenna on top of the tower is 113 feet high.

Here’s some more trivia for you. If a hunter at the base of the tower shot a .45 caliber pistol at a goose flying near the top, he would have to lead the goose by more than the length of a football field. If the tower had its base at the bottom of the Royal Gorge in Colorado, the antenna would still be 563 feet above the upper rim. In a 70 mile-per-hour wind, the beacon light on top sways approximately ten feet.

If a 20-second commercial started at the same moment a baseball was dropped from the top, the commercial would end nearly four seconds before the ball hit the ground. If an ironworker on the antenna dropped his wrench, it would be traveling 250 miles per hour when it hit the ground.

To get to the top, workers can either use a service elevator or a ladder – one might guess the elevator would be more popular. Once they’re up there, however, the transmission signals are so strong they can hurt the fillings in their teeth. Tune in tomorrow and Friday for two more tall tower stories.

Dakota Datebook written by Merry Helm

This text and audio may not be copied without securing prior permission from Prairie Public.

Dakota Datebook is a project of Prairie Public, in partnership with the State Historical Society of North Dakota, with funding from the North Dakota Humanities Council.

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