I invite and welcome your comments and suggestions regarding the application that is described in this discussion. 

I have been building and flying drones for about three years, and am early in the process  of adding collision-avoidance to my Phantom 2 Vision, and then to a 3D Robotics  X8+. Once I have collision-avoidance working on the Phantom, I would like to add a solenoid release mechanism behind the camera. 

The release mechanism would serve to securely carry fishing line to a suitable and safely accessible branch at the desired height. With a moderate amount of practice before attempting to place the line, I believe that the correct placement would be a reasonable possibility. The fishing line would then be exchanged for ⅜" Dacron line, and that would be subsequently exchanged for either an LNR Precision EF-QUAD or a Carolina Windom Compact 80 antenna.

Alternatively, I could skip using a release mechanism, and instead secure the fishing line to the undersurface of the UAV and simply fly up to the desired height, cross over the branch chosen to  support the line, and then land on the other side of the tree, allowing the line to be draped over a suitable branch. This would  be simpler than using a release mechanism, but I would still want to hold the fishing line in a RF-triggered release to be used only if the UAV became snagged in the tree by the line. If this happened, the line could be released, potentially freeing the drone.

Whether or not I have a functioning collision-avoidance system on the Phantom, I would use inexpensive prop guards for the Phantom available on Amazon.

True, it would be much easier to use a slingshot or a commercially available device("Antennae Canon") to lob a weight attached to fishing line into the tree at the desired height. I agree but using a drone to accomplish this would give an amateur radio enthusiast an inexpensive method to place an antenna at a much greater height than could be accomplished by a slingshot or antenna canon. Besides, I am not sure that I want a neighbor calling 911 to report that "a man is standing in a nearby yard shooting into the air with what looks  like a gun". One needs to be certain that the use of an antenna canon is legal at the location of the tree before using one. A drone avoids these issues.

I welcome any comments or suggestions about this concept. In particular I would like to know if anyone in the group has experience with buying or building a release mechanism for a drone. Does anyone know of any articles or blogs about using a drone to help place an antenna for amateur radio use?

Thank you,

Justin