Flying pole
A flying pole is the idea that for simple applications where one wants a static mount fifty meters high in short order, a tethered UAV is a very practical platform. Removing the need for a large battery onboard frees up space for payload, and for lugging the tether. The tether needs to be a high voltage line in order to reduce the amount of heavy copper required. Payloads may involve a wireless transmitter, an antenna aerial for pointing over obstructions, or more often a surveillance package for top-down situational awareness. The first commercial product is the SkySapience Hovermast, but several manufacturers are working on the problem.
The direct competitor for this application is tethered balloons, which may have problems with the sun, the wind, durability, and the unwieldy size.