|So you could be ~800' away. Probably not much out there for cheap but I recall a clamp on item called WiFire. You might check it out ($70-80) or see if something of this ilk is out there. No idea how well it worked.|
I recently read that tinfoil hats can amplify a signal instead of protecting ya from it so folding up a hat for your tablet might help.
Sorry, I'll just get my hat and coat...