On September 8, 1987 KIOA, 940 Khz in Des Moines became the first digital AM station in the World. The Harris Corporation decided to test the prototype for the DX-10 all digital transmitter at the KIOA transmitter site. This announcement article from Harris best describes the scope and results of the test.
Presently, KPRZ, the current occupant of 940 Khz, is using the DX-10 that was used in the 1987 test. It is DX-10 serial #2 and is the first DX-10 actually put into service at an operating station. #1 was used at the Harris Company Quincy, IL test facility. KBGG, 1700 Khz in Des Moines also runs a DX-10. WHO, 1040 Khz, has the DX-10's big brother, the DX-50, running 50,000 watts instead of 10,000.
Former KIOA Chief Engineer John Kosobucki also informed us that although 1460 KSO was the only Des Moines AM to ever promote the fact that they were running AM stereo (using their 1970's modified Collins transmitter), KIOA tested the AM 10, running AM stereo, for Broadcast Electronics in 1992-93 before John left KIOA. In other words, KIOA ran AM stereo for a while, but didn't tell anybody. John says that he still preferred the Harris DX-10 over the Broadcast Electronics AM 10.
KIOA Chief Engineer John Kosobucki with DX-10
See the DX-10 on a visit to the KPSZ 940 Khz site.
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