StoodRaindrop23:
Could you elaborate on this? I think it is a really good idea, I'd just need to know a little more of how to do it. How would I compare the time difference of the FOB signal from far away versus from up close?
I'm not familiar with the AD8318, so I can't help much with that module. Different sensors will measure different things.
How good are you at Physics? Have you looked into what happens to a waveform as it travels? Comparing changes in a wave's properties is a good way to determine how far away it is.