On Mon, 20 Apr 2015 20:36:48 +0100, Ian Jackson
wrote:
(...)

Today, we had Chen Dubin, owner of Santa Cruz Drones, gave a
presentation and a demonstration of his drones at the FLUG (Felton
Linux Users Group) meeting:
http://www.santacruzdrones.net/#content_area
Of course, I mentioned the idea of using a tethered drone aerostat to
support a wire antenna and asked how long the motors would last before
overheating. His drones have rather large motors, which he says would
last for days. He also mentioned that the military is already using
such tethered drones to hoist antennas. For example:
http://www.skysapience.com
http://www.droneaviationcorp.com/tethered-drone.html
https://www.google.com/search?q=tethered+drone&oe=utf-8
https://www.google.com/search?q=tethered+drones&tbm=isch

I also asked if he has tried any of his drones near the local AM
transmitter antennas (KSCO). It seems he lives nearby, hangs around
the station, and has not seen any problems. So, it should work at 160
meters. (The control links are usually 2.4GHz. Video is either 900
MHz or 5 GHz).

Since the main limitation of a tethered drone is weight lifting
ability, doubling the wire length and hoisting a 1/2 wave antenna is
easy. A half wave antenna does not need a ground plane, and might
work better than a 1/4 wave. End fed 1/2 wave antennas:
http://www.aa5tb.com/efha.html
http://www.vk2zay.net/article/115
http://pages.suddenlink.net/wa5bdu/efhw.htm
http://www.w8ji.com/2end-fed_1_2_wave_matching_system_end%20feed.htm



Drivel:
Kite and balloon lifting antennas for 160 meters:
http://www.qsl.net/g4vgo/
http://www.qsl.net/g4vgo/Kites.htm


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558