Adventures in Spark Gaps

I wanted to build a spark gap transmitter-you know, for fun. However, things didn’t start off so great. Here is how it went down.

My first plan was to build this.

I like it, but it uses an ignition coil and some other thing. However, check out the receiver. That’s awesome. It’s a coherer receiver (I think) and it basically detects a spark with those two bolts in the plastic sleeve. There should be some iron filings or something in between the bolts. When a spark is detected, the filings jump the gap and make it a conductor. I’m not sure why the LED light is connected to a 9 volt battery though.

After that, I just did some google searches for spark gap transmitter and attempted to build the designs I saw. None of them had capacitor values, so I just had to guess. But they didn’t work.

I honestly thought I knew how to do this. I tried a step up transformer with a capacitor. Nope. Actually, I was getting a spark on the battery side but not the step up voltage side. How did I even pass physics courses?

Here is my attempt with a transformer.