WLW: 1930s AM broadcast superstation

As entertainment delivery progresses from the broadcast model that was pioneered by David Sarnoff toward a content on demand model, it’s fun to stop and examine the roadside litter.

An impressive relic of the old broadcast days is the WLW 500,000 Watt transmitter located outside the city of Cincinnati. From 1934 until 1939, WLW broadcast a whopping 500,000 Watt AM signal on 700 kHz that covered North America from coast to coast.

Front panels of 500,000 Watt transmitter Photography by Frederick Vobbe, Lima OH
Front panels of 500,000 Watt transmitter
Photography by Frederick Vobbe, Lima OH

For most of its life, WLW transmitted 50,000 Watts, but in the 1930s it pumped out 500,000 Watts under a special authorization that needed to be renewed every six months. In 1939 Congress and the FCC reconsidered the wisdom of allowing a single station to control one frequency nationwide and withdrew the 500 kilowatt authorization. No other US AM station has ever been authorized to transmit more than 50 kW.

The 500 kW hardware was massive. Its final amplifier consisted of twelve water-cooled vacuum tubes with a plate dissipation rating that totalled 1.2 Megawatts. It was plate modulated by eight more 100 kW plate dissipation water-cooled tubes. This video walkthrough shows the oversized components that are still in place.

This excellent article on WLW in the 1930s claimed,

WLW was the 1930s version of NASA, continually testing the limits of just what AM broadcasting could do under U.S. regulation.

Powel Crosley, Jr. owned WLW. His factories produced radios, appliances, eventually TVs, and even cars. WLW provided the perfect advertising platform for Crosley products.

Today the tiny microprocessor, hair-thin fiberoptic strands, packet switching, media streaming, and especially content on demand technologies threaten the future of the once mighty radio broadcasting giants. Their giant carcasses remain as monuments, like the shattered visage of Ozymandias.

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