In this letter to the editor the author responds to Nick Langan’s Signal Spot column, “Connecting Currents on Campus.” Radio World welcomes letters to the editor on this or any story. Email [email protected].
I was an undergrad electrical engineering student at Illinois Institute of Technology in Chicago in 1961.
We had a brand new student union building, designed by Ludwig Mies van der Rohe. I joined a motley crew of EE geeks who were building the WIIT student-radio studio in the basement.
I didn’t know of any faculty advisor to guide us. We knew just enough about radio and electronics to be dangerous. We had a homebrew 640 kc transmitter in the dorm utility room, with a coax running to another dorm and the frat houses — kHz didn’t exist yet.
To couple the RF into the building wiring, there was a three-phase 120V receptacle in each building. We had a homemade box containing an RF transformer, three capacitors and three fuses that plugged into the receptacle.
In the newer dorm building, each student desk had a 20-watt fluorescent desk lamp which contained a 1-microfarad capacitor wired across the line either for noise suppression or power factor. But this resulted in a 120-cycle modulation of the RF.
The previous class of students had convinced the building electrician to install those three-phase receptacles without fuses directly to the main breaker for the utility room, hoping that would eliminate the hum. The small fuses inside the interface box were in fuse posts. When another student was plugging the box in, he happened to squeeze the box, shorting out the terminals on the fuse holders!
I thought I knew how to make a safer box. I used three fuse blocks for glass fuses. It really looked neat.
The problem was, I had selected small fuse blocks with instrument-rated fuses, not line-voltage fuses.
When I plugged it in, there was a big bang and the room got very quiet as all the circulation pumps stopped.
Fortunately it didn’t affect the rest of the building. But I had to notify the building electrician on a Saturday night.
Even though it was only 120V/208V, the fuse blocks had somehow arced over.
I graduated in the class of 1963.
Today, I see that WIIT is licnesed on 88.9 FM with an ERP of three watts.
— Ken Lundgren (K9RYR), Bloomington, Ill.
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