Here's a YouTube video of a voice contact from USA to South Africa. They eventually drop the power to one Watt. Evidently, the US station has a 200 meter long vee-beam (wire beam) antenna, but still, this is impressive! In Morse it would have been quite 'do-able, because of the virtual 13dB+ system gain of CW over HF radio.
http://youtu.be/NU5i_09nWjg (http://youtu.be/NU5i_09nWjg)
On the other hand, this is an attempt at a 15 mW contact using a speaker cone to generate the electricity to run a small transmitter by ... er, ... well yelling Morse code into a bean can. You just have to see this.
http://youtu.be/guIRbb8ETGg (http://youtu.be/guIRbb8ETGg)
My ex-wife could probably generate a kiloWatt this way, she could yell so loud and long...
73 de RadioRay ..._ ._
You could hook a generator up to my ex's mouth and power NYC for a month!
And then there's this guy who made a straight key with generators from flashlights in it that power the transmitter with each dit and dah.
https://www.youtube.com/watch?feature=player_embedded&v=LYpvU80nyvM (https://www.youtube.com/watch?feature=player_embedded&v=LYpvU80nyvM)
My wife brought home an old sewing machine treadle base. It's been sitting in the garage for 2 years. The first time I get boored I'm mounting a generator on it. That way I'll have a desk and power source in one portable unit. It would be a laugh at Field Day.