Whitebeard, for me at least, it's hard to say how far my sensor will pick up a target. There is a hillside going up from my bait site, so there is an angle involved. If you noticed in the coyote clip on page 67, the coyote, when shot, rolled down hill.
I have had the sensor pick up a possum that was above the bait, somewhere between 10-15 feet from the sensor. It probably will detect further, but the way the transmitter is set in relation to the ground and terrain can make a difference.
DoubleUp might have some information to add.
I have considered getting another Driveway Patol and setting the transmitter further up the hill. My hope would be to cover the area well and alert me when a coyote is near and maybe not necessarily right at the bait. Problem is that not all the units work on the same frequency, so it may be a hit or miss as to whether a new one would work with my current receiver. DoubleUP lucked up and got two that work in conjunction with each other.