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The Mighty 'MOX: 50kW AM Tower site tour

Nearing it's centennial, KMOX-AM (1120 kHz) is a 50,000-watt clear-channel AM radio station with studios located in downtown St. Louis, MO, USA.

But their broadcast tower is located about 10 miles northeast, in Pontoon Beach, IL. My Dad was the director of engineering overseeing the tower and studios for about 20 years, and though he's no longer there, he and I got permission from Audacy and the St. Louis engineers (thanks!) to tour the site, and learn a bit about how they broadcast their AM signal—which reaches all the way into Canada and Mexico at night!

Jeff Geerling holds a dumb not smart light switch

In this blog post, I'll write a bit about KMOX's tower system (AM towers are a lot different than FM, like the FM Supertower we toured last year), the transmitter, and the some of the history found at that tower site.

Is AM Radio Dead?

...that was the question I asked my Dad, a radio engineer for many decades, who worked at the biggest AM station in St. Louis, KMOX. The station is approaching its centennial in 2025, as are—some YouTube commenters argue—its primary audience!

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I recorded that video during my convalescence at my parents' house (I am feeling much better now, thank you!), and my Dad discussed a few reasons why AM radio—at least in the US—is not dead. But it is suffering.

In the video, I pointed out the current dichotomy:

A hospital stay and MLB blackouts led me to RTL-SDR radio

Last year I spent a lot of time in the hospital. Between multiple surgeries and outpatient visits and follow-ups (either intentional or through an unexpected ER visit), I probably spent at least a month or two in a hospital room. For a time, you could see the exact date ranges I was checked in by the holes in my GitHub contribution graph! Such is the life of an open source developer.

Jeff Geerling holding yay sign in hospital bed after surgery
Despite appearances, this was not a very fun recovery!