[Lowfer] how strong would half wave dipole be?

[Art]

Hi everyone,

I recently became interested in ballooning, and began to wonder about 
launching a 1 watt transmitter with a half wave dipole antenna. I 
have located a free helium source and a surplus balloon.

With small diameter wire (for light weight), how far could I be heard 
on 185 KHz if the antenna was oriented vertically, and flying between 
20K and 100 K feet above sea level?

Would the QRS signal be readable in the entire USA, or would be range 
be much lower?

Has anyone ever heard of others trying this?

Art