This from Steve Redick:

Here is some tremendous Chicago FD radio traffic I believe to be from  September 7, 1974. A 3-11 plus numerous other fires. This is from a friend’s collection. Some of the voices will be very familiar to many of you old timers. Some of the office voices: Tom Shevlin, Ron Kaiser, Irv Bisk, Hank Wilwers, and Jeff Scwartz. Some companies of interest: 25, 51, and 24. This recording has it all … a MUST LISTEN