Uploaded April 2011 | Updated September 2026, 1 day ago
Last night, I tinkered together a small 555 astable multivibrator. Today, I replaced the 2.2uF cap with 660pf of capacitance, which appeared to generate a square wave carrier around 540khz or so. By AC coupling a signal from my iPhone onto pin 5, I created an AM transmitter, capable of sending audio a couple of inches to my old GE Superradio II. The quality isn't terrific, but it isn't terrible. As an exercise, I'm trying to work out how the radio works, and how I improve it.
Last night, I tinkered together a small 555 astable multivibrator. Today, I replaced the 2.2uF cap with 660pf of capacitance, which appeared to generate a square wave carrier around 540khz or so. By AC coupling a signal from my iPhone onto pin 5, I created an AM transmitter, capable of sending audio a couple of inches to my old GE Superradio II. The quality isn't terrific, but it isn't terrible. As an exercise, I'm trying to work out how the radio works, and how I improve it.
