36 minutes ago, Brain said:

To be honest this is more of a hardware question and you might have posted in the wrong forum. This isn't generally a game developer thing and is the sort of thing best diagnosed with an osciliscope and an electrical engineer.

Have you tried the technical support offered with the device?

I agree. We have a scope but I am not an EE. And probably a logic analyzer is required for video signals.

I chose this forum because it is active and I am a hard core graphics game developer.

Does plugging the VGA->HDMI converter into a monitor's HDMI port instead of the DJI remote work?  It sounds like that converter should convert analog to digital, which is the only thing I could think of.

2 minutes ago, Hodgman said:

What's the big picture problem you're solving, btw? 

Our current onboard computer only has a VGA output and DJI only takes HDMI or Lightbridge inputs.

We are looking at adding an HDMI port to our computer but I was hoping a $10 VGA to HDMI adapter would be the fast/easy/cheap solution.

We are trying what you suggested now, thanks.

OK Hodgman, I see the problem now thanks to your advice.

I just realized, I think, that the Lenovo is pure HDMI. When you set it for 800x600, it is a lie! It is actually 1080p!

So when the Lenovo was at 800x600 the output was in fact 1920 x 1080. That is because, I think, it is easier to anti-alias 600 pixels to 1080 instead of 720 (or just dropping the lines which would be nasty).

The solution is not yet obvious but realizing the problem makes me feel a lot better.

16 minutes ago, Hodgman said:

Yeah, but what's the big picture problem that requires plugging a PC into DJI video transmitter? 

The drone has an infrared camera and an onboard PC with a frame grabber plus an interface to the drone for telemetry and flight control.

The big picture is as far as the eye can see. In our case, it is identifying things in the infrared spectrum and reporting that information. The user on the ground (or anywhere in the world) will have access to the camera images in real time.