|80m dipole up 90 feet. Ladder line allows use on 30 & 40.|
My quadcopter is the DJI Phantom 3 - I've also used the Phantom and Phantom 2 in the same way as described here. Since the later model Phantoms (3 and 4) don't have a spare channel available, I needed to use a separate transmitter-receiver to operate the payload release servo that drops a weighted line over the target tree.
Here's what I used in addition to the Phantom:
Cheap R/C transmitter-receiver
Payload release device
Add a reel of 20lb monofilament fishing line and a 2-ounce weight and you're in business.
The idea, of course, is to fly over a tree and then release the weighted line. The best way to do this is to fly well above the tree and then drop the line. This way the weight doesn't have to overcome the resistance offered by the tree canopy - it can fall free for a distance, gathering momentum before encountering any branches it has to fall through.
The Phantom (and perhaps other quadcopters) are well-suited for this in that they stay where you put them when flown in GPS mode. In other words, it's possible to "park" the drone above and on the opposite side of the tree from where you ascended. Its GPS fix will hold it there in position, within a foot or two, despite wind gusts or breezes. This provides time to pick up the other transmitter and actuate the control that operates the servo.
The weight will then drop, bringing the fishing line down with it. I then use this line to haul up a nylon cord which in turn hauls up my final antenna rope, usually a 5/16" line from the Wireman. My trees are 110 feet tall. Once the dipole is attached and both ends are hauled up, the 80-meter dipole settles to around 90 to 100 feet. I feed it with 450-ohm ladder line and have worked 30 zones on 80 meters in three years of DXing and 305 total DXCC entities in 5 years of using the dipole on 10-80 meters before installing a tower/Yagi.
If you've got tall supports, a dipole is an excellent antenna - and a quadcopter is a fast and easy way to get the support lines quite high and with a good degree of accuracy.
|DJI Phantom 3A fitted with receiver, battery and payload release mechanism.|
|A piece of scrap corner molding zip-tied to quadcopter holds the "antenna-raising" parts|