This is interesting and clever.

But it does not work with Flarm! Flarm/PowerFlarm is seeing rapid adoption.. A system that competes with Flarm has only the possibility of reducing safety during the time frame that I expect to remain an active glider pilot. Though competition is usually good, it is not a good thing to have competition in this case. What makes it worse is the possibility that any pilot might consider waiting for this instead of installing Flarm/PowerFlarm right now.

Just like Flarm, this system requires that both gliders be like equipped. Having a contingent of Flarm users and a contingent of WiFi users at a contest means that we cannot get to the significant level of safety improvement that would be otherwise achievable with fully adopted Flarm or PowerFlarm.

As I read through the material I couldn't find a single element of technical superiority over PowerFlarm. It seems to me that for one technical standard to replace another established standard it needs to be distinctly better than the first. Being equivalent (if it were) is not near good enough, even if the cost is lower. Soaring is not so strongly cost driven as consumer products for example and in general having an avionic component supported by a manufacturer is a very important benefit.

Starting from where the developers are now, they are very far behind PowerFlarm. Part of the goodness of PowerFlarm is the years of evolution in the algorithms for the collision risk analysis. In a fast changing environment of side by side cruising and close thermalling, PowerFlarm makes good determinations. Even the most brilliant programmer on earth cannot just sit down and write that code. It takes years of observation and feedback to make it work really well in the real world. The electrical components are not the major part of the problem; the magic is really in the software.

And for close proximate flight, I'm led to wonder how the designers might have come to the conclusion that 2-3 second latency would be acceptable for good warnings? Having flown with PowerFlarm, I have to believe that the latency is lower than that.

On the hardware side, I think there are things the developers are not considering well. The use of a high gain (5 dBi) antenna is not advisable. It's important to use a low gain dipole pattern antenna in order to couple well with turning gliders. With a low gain antenna at both TX and RX, the link analysis will be significantly impacted and you will not have the range that has been speculated. PowerFlarm uses a simple dipole for this reason and yet has greater range than is contemplated with the high gain antennas suggested here.

Also related to the coupling matter is the choice of frequency. 2.4 GHz will be significantly more impacted by the nearby human body and other items of near wavelength dimension in the environs of the antenna. This can be overcome to a certain extent with power margin but there isn't power margin. PowerFlarm provides an auxillary receive channel to partially address this issue. An auxillary channel is needed in spades at 2.4 GHz.

There is no mention in the article as to the level of degradation that might be expected in a contest environment with say 50 gliders all within radio range. What is the duty cycle of the waveform? How much would 50 gliders be expected to further reduce functional range?

In this self assembly scenario, who does the testing? One of the things about electronics in general and avionics in particular is the need for sophisticated testing. Having a manufacturer behind an avionics product means that the items have been tested. There is the production testing of each article as it leaves the assembly area. Even more important is that all of the components that go into the design have been technically qualified as suitable. That means that they are tested for operation over a wide temperature range as well as shock and vibration and humidity and pressure. They are tested for having a suitably small degree of parameter variance over the environmental range. All of the USB consumer items that are identify for this project are items that are generally made in China and are intended only for use at room temperature in benign environments. It would be almost remarkably if they all happen to also work over aviation temperature range. I'd be particularly suspicious about the radio module power output and the radio sensitivity over temperature; especially for a device that was never actually intended for operation over temperature.

In fairness the original poster, he did not describe the system as intended to be a replacement for Flarm/PowerFlarm. Yet as described, that would be the obvious thing that many readers might be considering here. For that reason it is worthwhile to point up these considerations and limitations.

Even as I hope that it eventually works well for OP's club, I'm also hoping that no US pilots in particular might be looking at this as a suitable substitute for PowerFlarm.