868/915 MHz LoRa R/C controll (2.8 Watt PA) testet at 100km range

[Marcel Wappler]

Hi All,

I just stumbled other this high altitude community as I was locking for some information I need to develop the system further. I've seen that some of the community are using standard LoRa modems from china (HopeRF) in order to communicate with their balloon.

So I'm asking myself whether there could be the need for driving the performance of such high altitude LoRa links any further?

For costumers flying First Person Video R/C Models we developed a quite sophisticated LoRa based R/C control system. The LoRa based R/C control system we developed was successfully tested flying model air planes at a distance of 100 km in the swiss alps. Some Features include:

- Operational in both 868 and 915 MHz, Band switchable on the fly
- Frequency Hoppping (FHSS)
- bidirectional: transmit control and receiver telemetry data
- Receiver has 2 transceivers (Diversity) to mitigate antenna polarisation fading
- receiver has a built in backup battery which allows to send last GPS position in the case of an incident
- dynamic power regulation: system always uses the lowest tx power possible

If anybody is interested in our customers system or a similar system optimized for high altitude use, let me now.

Regards
Marcel

[stuart....@catvog.org]

On Thursday, December 10, 2015 at 1:44:03 PM UTC, Marcel Wappler wrote:
> Hi All,

> So I'm asking myself whether there could be the need for driving the performance of such high altitude LoRa links any further?

Is it advice on LoRa you are asking for so you can improve your RC system ?

In the HAB world only 100km at 2800mW would be seen as a very poor performer indeed.

Using 10mW two way telemetry has been demonstrated at circa 250km and one way reception at around 450km, might even be further now.

More range is clearly possible, using more power for instance, but the limiting factor for LoRa in HABing is going to be the curvature of the Earth.

[cha...@thefnf.org]

Along these lines, I ran across this interesting article the other day.

https://www.balloonchallenge.org/winner_docs/SpaceTechDemo-MONSTER-team-Report.pdf

Using high altitude balloons, bladerf SDR, rasberry pi and a celestron
tracking mount.

Interesting quote:

"The HAB2 - GS link was operational through the whole flight and
achieved a final slant range of 91km"