Here's how I installed mine:

http://www.kissingfrogs.tv/scarecrow.html

I used the accessory bracket (hard to find) to mount it as the
blast it produces when it turns on is too much for the supplied stake.

I made a large dial so I can see if it's turned on before I step in
front of it.

Lost one Koi to a Heron before I installed it. None since. One Koi
got speared when I forgot to turn it on (he's since recovered.)

Steve J. Noll | Ventura California (zone 10)
| Glass Block Pond http://www.kissingfrogs.tv