Even if you knew what to do, convincing the naturally suspicious people back then to trust a strange outsider would be tricky. Then you have to get the right materials.

If I were a bit more clever, or maybe if I was 50 years older and had played with this kind of stuff growing up, I'd probably try to make a spark-gap transmitter. That seems to be in a sweet spot of not requiring too many super clever bits, and having obvious applications.