Just wondering if anyone has been able to succesfully use a USB hub connected to the Inspire 2 controller with your iPad/etc connected to the hub instead of directly to the controller?

Been testing all morning with various combinations and can't get DJI Go to connect to the controller if wired through a USB hub, but perhaps there's a specific type of hub that's known to work?

The reason I want to do this is I have a tiny HDMI to SDI converter that's powered by USB and I want to have this attached to the base of the controller so I can feed a professional video signal to video village on set. It would be really convenient to be able to power it from the USB socket on the controller rather than yet another external battery.

If your trying to power too many things from the controller you may lead into some issues.   First off the USB Hub will try to steal power, pluse your phone / tablet will try to steal power, and then your HDMI to SDI Converter will also steal power.  Don't quote me on this but I don't believe the controller is rated to handle that many devices sucking juce out of the port.

The maximum output power from the R/C via USB is 1.5A if you connect your power hungry iPad to the USB it will take all that and more if it could get it depending on state of discharge of the batteries.

I would not advise you to use a USB hub to the R/C output. It could introduce some latency and other effects from the HUB itself and maybe even cause disconnects.  

Simply get a power bank and feed the convertor from there. If that looses power at least you still have control over the Inspire....