Exploring a 1 MW FM Radio Tower with my Dad

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:

Shrewsbury FM Master tower antenna system by Harris near Crestwood St. Louis MO

I asked him about how the audio gets routed through the transmitter site, how HD (digital) and analog signals are mixed, how that's all routed a giant combiner room with 9" solid coaxial cables, then delivered through NO2 pressurized lines up to the antenna system 1115 ft (340 m) up in the air.

There's a lot of fascinating little details you might not think about when you see one of these masts sticking up into the sky, including support, grounding, cable management, transmitter cooling (including a rare sighting of a water-cooled FM transmitter!), and backup power.

Hopefully you find the video as enjoyable as we did making it! We're thinking of touring one or two AM sites in an upcoming video to show many of the differences when it comes to AM broadcasting. And if we're lucky, we might also visit one of the major TV towers in the area too!


Is it true that analog transmitters still use ginormous vacuum tubes?