I would like to find a device to reproduce Hertz's experiment that demonstrated the transmission and reception of EM radiation. The equipment as I recall used a Leydan jar, an inductance coil to boost the voltage, a capacitor with a gap that sparked, and separately a ring with a small (I believe adjustable) gap. Ideally, I would like to get a working model that looks like what Hertz used (OK, I'm willing to substitute a battery for the Leydan jar). Next choice would be something that worked the same, even if it doesn't have that "antique" look. If neither of those are possible, I'd be happy with some plans to build something similar. This would be for a classroom demonstration. Any leads would be appreciated!