1920s battery radios....how do they work?

[Kamakiri]

Originally Posted by Kevin Kuehn

The signal generator is probably acting as a coupling devise to your homes AC wiring, which is acting as a makeshift long wire antenna. The down side to using your homes wiring is that the radio will hear all kinds electrical noises riding on the power line. Even the ground wire to your homes electrical system may act as an antenna at radio frequencies.

You're 100% right because I have a wonky socket on the bulb on my workbench light....when it cuts out I can hear it on my radio 20 feet away.

Now, that said, I'd have to think there's a simpler way to make such a coupling device to do just that rather than use my signal generator. I tried coiling a wire around an AC cord thinking that might create a capacitive coupling, but no luck. I've searched out references to an .001 cap at a high voltage connected to the AC line somehow that accomplishes this, but can't find any direct references.