Strange things happen...
Was giving a satellite lab where we put two tiny "labsats" (spysats) with 2.4 GHz cameras about 1/4 and 3/4 miles away and then use a dipole with and without an 18" dish to show gain and the difference in path loss.
See the set-up in the right hand photo at the top of this page: http://www.ew.usna.edu/~bruninga/ea467.html
My technician placed the cameras out at 7 AM before class (both are across bodies of water, so the access distance is much greater than the line of sight path). I was giving the demo for the first group of Midshipmen and while looking at the image from the one camera, we noticed it moving and then saw a face. Looked out across the water (on the point of land right behind the dish in the photo) and saw a truck load of mexicans closely inspecting the camera. We were sure a full scale security alert would follow, because the string of "D" cell batteries inside a PVC pipe strapped to a dead tree sure looks like a pipe bomb.
Then we noticed something even worse. The truck they were in was carrying a NEW tree!
Fortunately, as everyone who works on a government facility knows, the diggers and the fillers are never the same crew. They tossed the new tree off the truck and drove away. SO my technician madly raced over to move the camera, while I madly scurried inside to call the local security to put out any brush fires...
Fortunately, we got the camera moved to a nearby light pole before the fillers got there and replaced the tree. Second lab period began, new tree in place as if nothing had happened. No security drill either..
The academy does things like that. Complete flower beds replaced overnight so that there are no dead flowers and there is always something in bloom. Oh, and no wonder all the trees are in good health... If it ain't, then it is replaced!
I was sure I was going to be spending the day chasing a landscaping crew to the nearby landfill to retrieve my camera and other goodies...
Anyway, these little $75 cameras at 2.4 GHz are a great way to bring microwaves and small dishes into the classroom. Just be careful where you put them. Oh, and plan on seeing LOTS of intereference from LANS.
For clear links, choose some of the $75 wireless cameras on 1.2 GHz which don't compete with LANS. But I think the FCC has cut off the supply of these coming in from China...
Bob, WB4APR