Ben -- Here's the directions I've used before:

Dry (in dehydrator) for up to eight hours.  Turn the meat to ensure even drying.  Dehydrated hamburger looks and feels like chunks of ground coffee.

I've given up drying hamburger, personally.  I'll carry the extra weight and avoid the work.  Once it's cooked, it'll stay pretty good, especially if it isn't exposed to air.  Now I just cook it, cool it, and seal it in my foodsaver.  But I admire your ambition!

prouboy