Today on Geerling Engineering, my Dad and I toured the tower site for WSDZ-AM, located in Belleville, IL. It's a 20kW AM radio station broadcasting with an array of eight individual towers:
How does one get a single coherent signal out of an eight-tower array? Enter the phasor:
That's phasor with an o, not phaser with an e, so Trekkies need not fret about a misspelling.
...except it was a beef frank. Make your wurst jokes in the comments.
What you see above is the remains of a hot dog after it has been applied to an AM radio tower operating in its daytime pattern, at around 6 kW.
A couple months ago, soon after we posted our If I touch this tower, I die video, a few commenters mentioned you likely wouldn't die after touching a high-power AM tower—rather, you'd have serious RF burns.
I was trying to figure out a way to somewhat safely test the scenario: what would happen if someone walked up and touched the tower, while standing on the ground?
If reading's not your thing, check out the short video we posted on Geerling Engineering:
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!
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.
KSDK-TV broadcasts to well over 1 million households in the St. Louis metro area. And my Dad and I went to their broadcast tower last month to explore how the digital TV signal is delivered through the air to so many people.
On our tour, we explored over 75 years of television broadcast history, seeing how things transitioned from thousands of volts down to hundreds, and from analog audio and video to all-digital.
And we even found strange artifacts of the past, like this random microwave dish that received a signal through the roof of the broadcast building for a time:
...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!
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:
As the son of a radio engineer, I've seen my share of radio towers. From small, rural AM and FM towers to urban 'constellation' towers serving dozens or even hundreds of services, there's a lot more than meets the eye.
My Dad and I visited the so-called 'FM Supertower' in St. Louis, MO twice now, to explore the tower and the supporting infrastructure below. Both of these visits are documented on our Geerling Engineering YouTube channel:
My Dad and I just posted a new video on the Geerling Engineering YouTube channel where we explored the tallest radio tower in the St. Louis metro area, the so-called 'Supertower' that has a 10-station combined dual FM antenna system (dual 4-bay FMVee by Dielectric) at the top:
Over on the Geerling Engineering YouTube channel, my Dad and I just posted a video where we installed the ASUSTOR Lockerstor 4RS - AS6504RS at his radio station, to increase their raw network storage capacity from 4 to 16 TB:
In the video, we focused on the installation, though I highlighted the unit's top-line features at the beginning.
In this blog post, I'll quickly recap the main features, then give more impressions of the unit from our experience setting it up, and my Dad's use of it at the station since we recorded the video.
I received a couple BliKVM units recently, and since I don't have as much of a need (my only 'remote' PC is about 2' away from my desk...), I brought them to my Dad's radio station, and we set it up in their main on-air PC so operators could access the PC and fix problems at home, instead of driving in!
Check out our video on this board on the new Geerling Engineering YouTube channel:
You can buy the BliKVM on AliExpress, and try your luck finding a CM4 to use in it!