Tonights presentation was provided by AA3WS and titled “How to modulate your IPOD.”
His main equipment was an IG-42 Heath Kit Signal Gen along with a 20Mhz scope.
The ‘test’ bench
Using a series of schematics, he showed how all signal generators are transmitters. The first schematic was of the sig gen which showed the three main areas of the board to include the oscillator, the power amp and then the modulator.
He then showed the schematics of several transmitters and noted how each transmitter contained the exact same areas.
As part of his demo, he connected the scope to the output of the sig gen to show the unmodulated sign wave being generated by the sig gen. Using one of the small FM radios (seen in the above picture to the right end of the table) he tuned into the frequency so we could hear how the unmodulated signal sounds (which is nothing).
He then connected his iPod to an impendence matching transformer, audio amp and an isolation transformer and taking that output, plugged it into the input to the sig gen. As if by magic, we were then listening to the music from the iPod.
Charles then proceeded to provide an example of both overmodulation and under modulation so we could both hear it and observe it on the scope.
Normal sign wave 
Some modulation added