History of NOAA Weather Radio KWO-39 in Chicago
First NWR brochure in Chicago The first weather radio system in the Chicago area was originally dedicated to the aviation user. It began operation in 1954, and continued until 1958, when the aviation broadcast was terminated. Ivan Brunk, Meteorologist in Charge of the Chicago U.S. Weather Bureau office at that time, suggested that the radio be put to marine usage on an experimental basis. The marine weather broadcast was an immediate success, and the service became permanent in May of 1960. The image at the right is from a brochure announcing the marine weather broadcast.

During the 1960s programing was expanded to include weather information for the general public, as well as the marine community. In the early 1970s, the forecast office moved from the University of Chicago, to a location on west Pershing Rd. The 300 Watt transmitter was located on the roof of the six story building.

Big changes came to KWO-39 in 1975, when the transmitter was moved to the top of the world's tallest building, the Sears Tower. Along with a much taller site for the antenna, the transmitter power was boosted to 500 Watts. This effectively doubled the range from just over 20 miles, to around 40 miles. 24 hour weather information was now available for the entire Chicago metropolitan area! A dedication ceremony was held for the new transmitter at Sears Tower on August 14th, 1975.

For many years, the broadcast equipment consisted of a rack full of tape decks, which would cycle individual messages in sequence. These tape machines saw years of continuous use, and remained in service until July of 1998. At that time, the current Console Replacement System was installed, and now provides automatic text to voice and scheduling functions for our radio broadcasts.


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