Thursday, February 23, 2012

Systems School

I had just (it seemed) been through this school and now I was re-joining it as an instructor. I had been taught about forms of voice radio (VHF and UHF frequencies). navigation (TACAN and Inertial Navigation) approach control (ILS), and radar identification (IFF). Now I was to teach these subjects.

My first assignments were to reacquaint myself with the materials to get ready to teach these subjects. I thought back to the remark by my fellow students that I would never succeed because I had no 'war stories' to tell.
I was among instructors who had years invested in teaching this material but it seemed, without anything against them, that they were mostly just presenting the same old information. I had been through this and I didn't get any enthusiasm for the subjects. Now this is fairly hard to imagine in these dry electronic subjects but it seemed that enthusiasm is just what was missing.

I had already introduced, in Fundamental Electronics, a glimpse of my instructor style. I had presented the 'Mary Circuit'. A particular circuit in digital electronics (named the Exclusive-OR or XOR circuit) which receives two inputs, each of which can be ON or OFF. The output of this circuit is ON only if ONE, and only ONE of the two inputs is ON.

So I had introduced the 'Mary Circuit' - Mary has accepted an invitation to the prom. In fact she had accepted invitations from two different boys, Joe and Tom. Now it is 'Prom Night' and Mary is up in her room. Does she go down to the front door if no one is there? No. Does she go down to the door if just Joe is there? Sure. Does she go down to the front door if just Tom is there? Sure. Does she go down if both Joe AND Tom are there? Noooo!!! Thus the Mary Circuit.

So I received inquiries in Systems School about this 'Mary Circuit'. They were very literal and not very receptive of innovations. This would change.

The navigational signal presented by a TACAN (Tactical Air Navigation) antenna was very complex. It provided, in one signal, both direction and distance information to any aircraft which utilized its signal. The signal presented one indication when its rotating signal pointed East, with additional signals which indicated how far from East it had moved. Simultaneously it presented information to an aircraft how far away from the antenna the aircraft was. Obviously this was a very complex signal.

But this signal was to be taught with a few diagrams in a workbook. This was unacceptable. I, instead, had students in front of the class, spinning with an flashlight pointing out toward the class, another flashlight pointing upward and emitting 'beep' sounds when pointing in a particular direction. The students, after many hilarious minutes, came to understand how they could determine their relative bearing from the antenna (student wielding the flashlights) by listening to the beeps and watching the rotating flashlight. Similarly they could determine their distance from the antenna/student by listening to the pattern of other beeps.

The understanding of this signal was allowed, in the official teaching guide, a full day for presentation. In one hour my students could not only identify the different components of the signal but their importance in providing the information intended. In fact other classes, composed of cross-training older students, asked specifically for me to present the class. 'Students' older than me ended the presentation in laughter but also with full understanding of the subject matter.

Some of the components of teaching - engagement of the students, the importance of humor in attracting attention - which I had learned in my college classes - came to full use in these classes.

At some future time I may relate my use of the 'Official Invisible Air Force Bowling Ball' in teaching the principles of inertial navigation.