Most of the published material about using the power on the Telem-1 port stems from the RFD900 SiK radios – because of it’s potentially high loads. It’s specifically addressed here on this Ardupilot Wiki page.

RFDesigns mitigates this by publishing data on the power utilization based on output.

Knowing this issue I probed it when I was considering my first designs for the electronics on my Holybro X500 X2. I brought it up in this forum entry – and specifically mentioned iVue’s use of the Holybro SiK radio as an example.

I also brought it up on the CubePilot group on Facebook – and the responses were pretty interesting. This group is more of a marketing outlet for CubePilot than a support source – so the responses from the CubePilot spokesman, Philip Rowse, went from benign to dark as the thread proceeded down the rabbit hole.

Now these threads have been purged from Facebook.

The initial responses from Philip were something like “just be careful”. And when I mentioned that I’d be sure to set a low enough power level, he became a bit hostile in his responses. He stated that using power on the Telem-1 port can have negative effects on other pixhawk circuitry. I pressed him to provide details, but he refused.

On a comment to one of my posts that have since been removed, one user offered that he thought that the power on telem-1 was tied into the USB circuitry. But no one seemed willing to detail the limitations.

So the Holybro SiK radio is likely to be OK. If there are plans to use more powerful radios, I’d proceed with caution.

From a practical standpoint, the greater issue is probably radio range.

We spoke a bit about failsafe in yesterday’s conference call. The ArduPilot failsafes are more complicated than what’s presented on QGC – and are worth some study. They aren’t as simple as what you find on a DJI product.