Obviously you think in terms of camera drones.I’m not sure I’d put the time and expense into the conversion if all it was going to carry was a small action camera.
Actually, I don’t but the use of a tiny camera did not visually demonstrate the load capability of the 920 airframe.Obviously you think in terms of camera drones.
Lots of good questions!Very Interesting design...
The LTE coverage... any tests yet to estimate range?Lots of good questions!
Double radio was choosen because in Germany LTE uses several different frequencies. In rural environments, typically it uses 862 Mhz for upstream which is quite close to 868 MHz and it uses much higher transmission power, so 868 MHz gets disturbed by close-up antennas. Here 2.4 GHz provides good range (about 2 km with CE conform power).
In urban environments, it's the other way around: Here the LTE works on different frequencies (e.g. 1.9 GHz), so 868 MHz gets less disturbed. On the other hand 2.4 GHz is heavily disturbed by WiFi WLans.
So my solutions adresses both downsides. Currently BVLOS flights are not generally permitted in Germany but I am working on special permits.
Motors are currently not replaced but may be in the future to get a more efficient setup.
Temperatures are currently only reported on the ground station as part of the extended telemetry. No automatic action taken so far. It was important for me to see how the ESCs behave in the closed body (only getting some minor ventilation by the fans in the bottom).
As you may have seen, all flight sensors of the original design were removed and replaced with up-to-date components.
I did not use the H920 prior to modifications, so I can not compare. From other videos I have seen, my retrofit seems to be more stable and especially the landing is much more painless.
I did not finally decide on the FPV camera. May be, I will just switch between FPV and external HDMI, may be I add an option to mix them together (side-by-side or pic-in-pic or even overlayed (in case second cam is a thermal camera)).
Regarding the batteries I added a post in the replacement battery thread. It is a double battery pack that fits in the given bay.
My error... wasn't suggesting organ transplant payload, just using that as an interesting example of BVLOS with medical.LTE range is theoretically unlimited as long as the ground unit and the air unit can reach a cellular network transmitter tower. Anything between goes via internet, so that the pilot can sit in Norway and the drone can fly in New Zealand (ok, with some latency...). The other question is, if you have LTE (4G) coverage (3G is also ok for control and telemetry but with more latency) at all in the area where the drone operates.
Within a certain range, the drone can also be operated without cellular network due to the radio module redundancy. Also this range can be extended using relay modules that for a mesh network.
Regarding the organ transport, I think it will require drones with more payload.
We are currently developing a battery powered multi-rotor drone that can fly 10 kg for about one hour.