Bud, just a quick post script to the air check stories - we had a reel-to-reel tape machine in the control room that was dedicated to DJ air checks. Some DJ's recorded every show, and others recorded sporadically. I seem to remember Wayne Moss recording many of his shows.
If the DJ wanted to record an air check, all he had to do was to thread a fresh reel of tape onto the machine, and then go to work. The machine's remote control was connected to the studio microphone key. Every time the microphone was turned on, the machine would begin to record; then when the microphone was turned off, the tape machine would stop. (As an alternative, the DJ could use the tape machines standard remote control to start and stop it on their command).
Pat Walsh also had a small fleet of portable radio/cassette recorders that he would use to record things he was interested in keeping.
The reel to reel recordings were usually good quality - since they used the studio audio as its source. Pat's cassette recordings were not always good however, medium to poor quality and subject to reception noise where-ever he happened to be at the time.
Felix also ran a "logging recorder" at the transmitter. It ran at incredibly slow speed (much slower than 1 7/8 ips) and was used only when there was a question about something on the air, a commercial may have been left out, or just as a legal verification of the program material. These logging tapes were poor quality, and their use was limited to verification of the program content.