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A Technical Look At KMOX

By Meryl Friedel

KMOX transmitter 1933
KMOX transmitter 1933

If you’re statistically minded, here are a few numbers to keep you busy:

—To cool the 35,000 watt tubes that are used in the 50,000 watt KMOX transmitter, distilled water is circulated around the anodes (an anode is the plate of the tube) at the rate of 108,000 gallons each broadcast day, which makes 90 gallons a minute.

—To dissipate the heat absorbed by the water, it flows through mammoth radiators, through which four large fans force 18,000,000 cubic feet of cool air each broadcast day and that means 15,000 cubic feet per minute.

—The anode of each tube carries 17,000 volts.

—Each 35,000 watt tube costs $480 and a 50,000 watt radio station has to have eight of them. —1200 feet of messenger cable, of which 600 feet is in horizontal suspension, supports a 279 foot antenna between two 300 foot towers. One end of the messenger cable hangs free and is coupled to a 2700 pound block of concrete which acts as a counter balance to the combined stress exerted by the 279 foot vertical portion of the antenna and the 1200 foot messenger cable. The concrete block also takes care of the contraction and expansion and is a safety factor during all kinds of extreme variations of weather.

(This seems to have turned into a description of the physical mechanics of a radio station transmitter. As clearly as this simple layman can get it, the above towers, antenna, etcetera, are what actually send out sound on our prescribed airwaves.) But to get back to the statistics:

—342 miles of special telephone wires are used to broadcast KMOX programs that originate outside of the studios.

KMOX Meramec transmitter building 1931
KMOX Meramec transmitter building 1931

—5,068,000 watts of electrical energy are consumed each broadcast day by the KMOX 50,000 watt transmitter. That energy, if used to light a 60 watt bulb, the size generally used in homes, would light more than 91,088 such bulbs for an hour. Which gives you an idea of the electrical energy necessary for a radio station which is as powerful as is allowed in the country.

Not being a statistician, these figures have made us dizzy. Hope you have fun with them. Graham L. Tevis, KMOX Chief Engineer, is responsible for these facts, so you may be sure they’re both true and authoritative. Hope this has also answered some of your questions about what makes the wheels go ‘around in this thing called “radio.”

And if you’re still interested in statistics, why not try to figure out what you could do in your home if you had all this light, water, money and so on, to use? We’d like you to tell us what you figured out, if you do.

(Originally published in Radio & Entertainment 09/23/33.)