Please be precise.

I did it at 100.5 feet

about 1.5 feet...i 'unlocked' the car from about 60 feet away.

well...as for precision, I'd say an acre. Someone else can do the conversion. (though that's just the furthest i've done...I could do from 1/4 mile if I want, oh, and that was opening the car, not just unlocking!) :)