Tethering and Powering Drones (DJI)

[LimitedPowers]

I'm in the research phase of my new business. I just received my Part 107 Drone Operation certificate and I'm in the process of getting my technician class HAM license in the US. I want to enter the UAV and telematics industry, but I'm not sure what niche I can operate in. The demand seems to be on the supply and manufacturing side right now, with everything UAV related either out of stock or outrageously priced.

I did notice there hasn't been much development in drone tethering tech. There's lots of good reasons why you'd want to operate a tethered platform, especially for radio antenna applications and other RF mesh type systems that are limited to LOS or have limited power. The tethers I've seen on the market are outrageously priced or marketed to institutional buyers. I would love to see a proliferation of drone tethers, especially for DJI.

Perhaps this is a good starter project for my company. Has anyone here tried to use a tethered drone before? Dronetenna anyone?

It looks fairly simple electronically, a base unit provides DC power, maybe 100V @ 1.5 amps or so, up through a thin stranded cable to a battery adapter that houses a DC buck converter that converts the supply power into something the drone can use. This same tether wire can be run alongside a vertical antenna for a wide range of frequencies, with a radial attached to the ground unit. You can also use a tethered drone as a LoRa or other digital node, or even as a repeater for other bands. You are really only limited by the 400' AGL rule in the US and that's a lot of antenna height for any amateur station operator.

Many neighborhoods in the US have rules against big antennas but you can fly your drone anywhere allowed by the FAA. You can even fly a tethered drone in otherwise controlled airspace, or so I hear in the new rules. Dronetennas might be a breakthrough application for RF and tethering. What do you think?

 

[Cafguy]

I like the antenna Idea, BUT Put it on a balloon..Drones use batteries.

 

[LimitedPowers]

The idea was to use a tethered power source as well, allowing extended flight times only limited by weather or base unit power. A balloon is an interesting idea, especially if inflated with self-produced hydrogen. But a balloon is fussy, unportable in the field (think about all the steps and items needed to launch a balloon to do anything useful), delicate, and more influenced by tempurature and unfavorble wind. A drone is self contained, portable, and can be deployed in moderate winds.

 

[GadgetGuy]

The idea was to use a tethered power source as well, allowing extended flight times only limited by weather or base unit power. A balloon is an interesting idea, especially if inflated with self-produced hydrogen. But a balloon is fussy, unportable in the field (think about all the steps and items needed to launch a balloon to do anything useful), delicate, and more influenced by tempurature and unfavorble wind. A drone is self contained, portable, and can be deployed in moderate winds.

Considering that these are intended for extended periods of time, the portability and deployability are secondary. The tethered balloon is a much better idea and is completely silent, with no associated drone hysteria. Your biggest challenge will be finding paying customers, who will be much more receptive to a silent tethered balloon than a flying drone, IMHO.

 

[BossBob]

Are you sure you want to use DJI equipment given the government attitude towards the country? Probably better going for MAGA drones or something that sucks up to the current administration!

 

[Cafguy]

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[LimitedPowers]

Nice link. I would want to operate without batteries though. It looks like his module is being inserted in parallel and operating as a charger pass through. Looks a bit cludgey. The M30 has a lot of lift so maybe it's easier to get away with a bulky solution. I want light, thin, and minimal, so maybe DJI isn't the best platform to consider. A custom designed Pixhawk platform that just works as a tethering platform and has large propellers with lower RPM might be a better roll. No camera needed, just gps and ground tracking. Telemetry is limited to its operation as a stationary platform, and optimized to lift communications equipment like relays and antennas. I really want to invetigate the integration of a tuned dipole antenna in the tether itself. Originally I thought maybe a vertical antenna would be lighter but it looks like that might need radials at the base unit which seems like a PITA.