posted on Apr, 6 2009 @ 11:45 PM
I know the ones we had in special ops had an 500 ft radius per FM sensor. We also had line attached sensors with 150 ft radius but remember I was
retired in 1986 by way of a mortar, meaning that they probably have MUCH more sensitive ones. (Yes, they work when it is raining and you can even tell
the difference between a four legged animal and a two legged one; BE CAREFUL.)
When my friends and I had just parked and walked less than 50 feet off the road at the Sumter site, we were surrounded and arrested for trespassing.
I figure they had inferred and thermal imaging remote cameras with sensors as they knew how many were in our party and the direction we were headed;
quick and efficient. This was during the early days of the Patriot movement.
[edit on 4/6/2009 by SGTChas]